I really like the faction. The overall mechanical theme seems to be something like sustain/control - either the units are really hard to kill, keep getting healed, or you’re just not allowed to play the cards you want to. Pretty different to what there is already! With so many fan factions now (at least 3 full factions, and a selection of other specs) perhaps the next X-tournament might have those fan specs people agree are balanced enough allowed as its X element!?
I think there are probably a few balance changes needed - we found that Grey was significantly weaker than we expected on the first test, and this looks similar. My thoughts:
Hope
Gloria and Gwen - really cool, but very difficult to balance! Getting 3/6 of stats for 2 gold seems obscene turn 1 and 2, never mind that Gwen is a bigger haste hero than Zane! Gwen’s damage ability doesn’t balance it out too much, especially with Gloria on the field. Needs nerfing. Some options: Get rid of haste on Gwen and nerf both of their stats to a TOTAL of something like 2/3, or do something creative. Maybe Gwen can’t attack until she is higher level? One idea I was toying with for “rule breaking” in Grey was having a hero who gets shuffled into your discard when they die, and then can be played for “0 and draw a card” from your hand to return them into your command zone, but I could never make it fit with one of the heroes there. Maybe this would fit with Gwen as a “Wanderer”? I still think they’re too good T1 and 2 and need nerfing, but this would lessen their impact later in the game.
One idea could be to have Gwen require a hero slot ie she cannot appear unless you have a tech 2 or heroes hall already. This would limit their early game impact for pay off later, which seems to fit with the Gold “sustain” mechanical theme.
Later bands on the heroes - Gwen’s maxband is a better version of Midori’s midband, which is fine, it’s a maxband; her midband is a slightly better Argagarg midband (as it’s permanent). So, both seem fine - and not weak enough to balance out getting Gwen on turn 1/2! Gwen - Midband, cool with the ultimate, maxband - what does this mean?
Hope spells - Remedy, we had a spell quite like this in draft 1 of Grey (the original Forgive) and it was too weak to play. You would usually just rather tech another unit, because that’s useful even if you have no units on the board. Could probably cost 1 or even 0 if it reamins unchanged. Overdose - cool! A cheap kill spell with a downside, which lets you use the healing effects. However, with a maxband Gloria it one-shtos a tech building, which may be too much. Healing sphere - seems a lot worse than Soulstone - an indestructible unit still exhausts at 0hp so isn’t even a good wall in your patrol zone (This is why the Good ultimate we made reads “cannot be reduced below 1hp” insteadm though that still leaves them vulnerable to deathtouch and “destroy” effects). Perhaps add some stat buffs? Or make it a lot cheaper?
Tech I units - need buffing I think? Medic = Saviour monk, which is a White starter card.Also compare to Fuzz cuddles, which very rarely gets played for double the healing and one more health. Priest = a strictly worse Sparring Partner.
Tech II - needs a lot of buffing as well. A general point: I notice there are not many high health units, which means that units will often die in once hit… so who benefits from the healing? In Good, we went for high-health low attack so that healing would be relevant. Here, I worry that there is very little synergy with the healing theme in terms of stats.
Cards specifically:
Medicine man - seems a bit too random, which is less fun. We had our White Knight like this initially, before deciding it is too frustrating. The only card with a coinflip in base codex is Ricjety Mine, which ALWAYS gains you at least 1 gold overall. With this, you use a tech II tech slot for a card which may actively hurt you -. We fixed Hanno by adding MORE randomness (more coin flips --> actually less random overall because you are bound to always get some heads). Maybe something similar could be done here, or alter it so benefit is more likely Roll a 6 sided dice and heal that much -1?
Faith healer - Cool!
Master Surgeon - weak stats for a tech III, and very few good targets? Very situational - can heal Rook or other 2 lives things, or take a sword rune of Grave. This stuff is cool, but compare to Flagstone Spy, the other 3/3 for 3 tech 2 - an abiity which is powerful and always relevant, even if that card rarely gets played! Maybe just make this a 4/5 at least?
Hospital - Tech II buildings should have really powerful effects to balance out the fact they can’t patrol and you lose a tech II unit to put them in your deck. Cf sanatorium, training grounds, morningstar pass, plague labs. This building is fuzz cuddles with no stats for one more gold! It could reasonably have something like healing 5 I think (and maybe cost 4 then)… though again, there are no high health units to benefit from this atm!
Mortician - Cool - not much gives you lots of gold in the game! But power wise, compare to Necromancer. That’s 3/3, with long range, for quite a similar effect, whilst this is 2/2. So could have a buff.
Tech III - I like her, a bright mirror to plague lord. However, comes off worse in power I think. The Lord costs 1 less for 1 less stat point overall, but is relevant even if you don’t have a board and can help you come back from behind plus does some direct damage. Meanwhile, if you don’t have lots of units, Martha isn’t very impactful! How many units do you usually have on the board in late game - 2 or 3 if you’re ahead, 0-2 if you’re behind? So Martha will give not many buffs. Perhaps make her cheaper and make her affect heroes too, and give her another effect to mirror Plague lord - healing to your base reliant on 1/1 runes perhaps? Base healing is a design space which Hope could really lean into, come to think of it.
Justice
The “this is the opposite of what it says” naming theme took me a while to work out, I think because it’s not entirely consistent? Eg Unyielding crusader is kind of unyielding, and Studious Templar is kind of studious. Cool once I got it though.
Mechanics general - have to consider how this load of soldiers would interact with Battle Suits. Would that make it too powerful?
Arthur stats and abilities seem good and maybe balanced at first glance. Don’t I know him from Hearthstone? 
Spells - Smite, cool. A bit less damage than Flame arrow for one less gold. Lay on hands - needs a buff, compare to Ready or Not, which does the same for one less gold AND prevents your opponent’s units from readying. Aura, could probably buff, compare to Speed of the Fox which does more for the same price. Call to Arms - Awesome, really like it. Reminds me of Living Mana in Hearthstone. Inspired by than - it might be cool if rather than just dying on your next upkeep, the soldiers had “Dies - Gain a worker” on them? This would cripple you for a couple of turns but you get to keep some soldiers. May be less balanced. Would be DEGENERATE with Ritual of Keter’s Rise if a game ever involves Grey and Gold…. But that’s FUN
Tech I - Reinforced Plate is fine as an upgrade, but mayyybe weak as a tech I? Obviously compare to Battle Suits. +1 armour might be a little stronger than +1 attack as more survival --> extra attacks --> more value for units, but still, this card would be hard to tech over a tech I unit with more immediate effect. Maybe a 2 or 3 cost card in the Gold Starter?
Cowardly Deserter - Powerful, but also costs 4, so might be OK!
Tech Iis
Sentry, Crusader - scary. Swift strike can be REALLY oppressive I think! The key swift strike unit is Glorious Ninja, which is made super good (like maybe top 5 tech Iis in the game?) by having swift strike AND haste. Both of these are weaker than than because of the lack of haste. However, there may be a critical mass of swift strike units that becomes un-fun to fight. Will require play testing.
Merciless warrior - less stats for the price of a Rhino, and an ability which is… a benefit, maybe, vs patrol? Cool, but feels maybe weak?
Templar - Flagstone spy, but without Invisible. Since Spy rarely gets played, this is definitely a bit weak without the sneakiness.
Fortress - see comments above on power of tech II buildings. This is 5 gold do nothing the turn it is played, and then lets you hide units, I guess so that they can attack the next turn - but this prevents them from patrolling, so you might just die! Compare to Fox’s Den School, which is cheaper, invisible, works automatically on ninjas, and doesn’t wear off when they attack! Also cf Eyes of the Chancellor - very similar effect, but has haste, has another powerful effect, and an upgrade so can’t easily die.
Tech III - Haste is really powerful, so this is probably fine as a tech III even though it requires you to have other cards in hand to work! Very scary with the swift strikers. I like it.
Destiny
Some really cool ideas in Destiny - this is my favourite spec in Gold mechanics-theme wise. It might need lots of testing though - one has to bear in mind that cards need to be fun to play AGAINST as well as with, and too much control of your opponent can be bad even if it at a level that is technically “balanced”.
Persephone - Seems good, at least pre-playtest! We ended up making a hero that was 1/3 at base 2/3 because 1/3 was difficult to play and have it be worth it, so that might be worth considering. Also - I really like the midband ability, but there are no other cards at all in Destiny that would actually benefit from it! And actually very few in Gold in general (Smite, Overdose…?). I really like the ability, so maybe some can be squished in somewhere?
Spells: Submit, cool, seems nice.
Pick your poison - TERRIFYING. I really like the idea, but balancing an effect like this and making sure it is fun and interactive for both players is going to be HARD. At present, in the context of the current Destiny it is probably weak as your opponent should be able to keep a cheap unit on the board I think. You would probably play it when running Justice Tech II and using the swift strikers to kill things. However, in codex in general… not sure. If you manage to build up a board big enough that you can kill off all their units and then play this, you probably win the game I think? Needs lots of testing, may have to become an ultimate spell or be reworked a lot!
Dogs - quite overpowered I think! 6/6 of stats on turn 3 if you tech it first and manage to have Persephone survive from your turn 2, and then the dogs come back! Seems to be based on Birds nest - there, the big advantage of flying is tempered by the fact that they only have 1 health, which is a lot less than 2 because it means towers and things like deteriorate cn kill the birds. Also the birds are pretty useless defensively as things run under them. The dogs will be tanky patrollers without these drawbacks. Actually better compared to Rambasa twin - the same cost there, but for 2 less health total, and they don’t keep coming back.
Command - Hard to evaluate balance, but maybe on the weak side for an ultimate? Which is fine, there are weak ultimates out there. However, I would be tempted to actually nerf it further, and swap it with some version of Pick your Poison as the ultimate…?
Tech Is: Dark Seer - way too weak. This would fit in a starter deck. Apprentice - Cool! I like it. Some anti-synergy with Submit, but that’s ok I guess.
Tech II: In general, the lack of stats and immediate effects here sacres me. There’s lots of cool effects around, but none of them will matter if your opponent is just running Rampaging Elephants and you can’t deal do or cope with the damage! I feel like you will be in a position where you know what youropponent is going to do, but are powerless to stop it. Nightmare.
Cassandra - cool, but probably too weak. Just a 3/4 for 3 the turn you play her as you can’t DO anything with the cards you see yet, and them be tech I stats not tech II stats (cf Argonaut, Cantaur). Honestly, I would scrap Dark Seer and make this the other tech I.
Tarot Scout - a 3/3 for 4 is again a bit weedy, even if the effect is big.
Hanged Man - this is nice! 3 gold, kill a unit and get a 2/2. If we assume it’s “active player chooses” which units die, defending this for one turn is very good. Might even be ok at 2 gold…?
Strength - I don’t get the name - is that one of the Major Arcana in Tarot? Anyway - seems thematic and could be balanced, depending on how much it costs! Since it is a “permenant” effect, probably 4 or more, or even 5 if the rest of the tech allows you to play it from a position of strength. Consider having a timer on it, something a bit like Fading in Purple, to make it less oppressive if it playtests as too good.
Zodiac king - probably a bit weaker than Necromancer? I’m not sure how it fits into the theme, though that can be fine.
Tech III - Haste and unstoppable, so an immediate effect and kills a tec h building, but certainly doesn’t “probably win the game” so a low tier tech III. I’m not sure the rest of the tech is strong enough to justify a weak tech III at present. I also think it could be more thematic - perhaps it is the harbinger of doom somehow… accumulates a counter with every attack, and can sacrifice 3 counters to do 7 damage to the opponents base or something?
SO I got carried away there! I have been thinking about codex balance a lot recently so was having fun thinking about this new set of cards 
I really like the set overall, and it should be fun after some adjustments. Dwarddd and I decided to just jump into testing with a rough first draft, and I think that has worked well. I think for this, there should be a few changes (a nerf on Gloria/Gwen, building buffs, Tech I buffs, more stats in Destiny Tech II) and then you should do the same. Would be happy to playtest! 
I really like the set overall, and it should be fun after some adjustments. Dwarddd and I decided to just jump into testing with a rough first draft, and I think that has worked well. I think for this, there should be a few changes (a nerf on Gloria/Gwen, building buffs, Tech I buffs, more stats in Destiny Tech II) and then you should do the same. Would be happy to playtest! 