Just a quick add-on to your discussion(s) on why beats :
One aspect of the MU that I think most do not give enough credit to is the two characters' attack speeds. ALL of Gloria's face cards effectively beat any attack from Argagarg except AA. In most match ups, Arg's 2, J, and most importantly Q, act as fairly good keep-away tools. However, this is definitely not the case with Gloria.
Arg's fastest non-AA attack is Q, at 2.2 speed and 9 damage. Note: ALL of Gloria's face cards are 2.2 or faster. Now, if Arg Q clashes with Gloria J, Gloria still gets to heal and return it to hand. Sure, she technically still takes 5 damage that round, but that's fairly little. If she does healing touch afterwards, that number goes down to just 1 damage, before Hex. More importantly, though, she gets the J back (while Arg loses Q forever) and, if she has spheres up, still gets to activate them. Advantage: Gloria.
If Q clashes with K, both characters take 9, but Argagarg is then knocked down (very bad for him), and Gloria can still do Healing Touch, meaning she really only takes 5 damage. Advantage: Gloria.
Her Q just cleanly beats Arg's Q.
All of this is to say, I would argue that her healing is not necessarily the biggest obstacle Arg faces here. The bigger problem for Argagarg in this MU is that he usually loses any attack clash or throw clash.
This is an even bigger problem because he absolutely needs to be aggressive. Bubble Shield can't really be relied upon to shut out attacks like in most MU due to Gloria's healing, so Arg must be on the offensive here. But, Gloria effectively has the dominant throws AND the dominant attacks. It doesn't help that she can recur them. Arg either has to simply Be Right a lot, or he has to catch Gloria on a particularly awkward hand (i.e.: a hand with few or no face cards) and manage to efficiently exploit it.
This is also why generally, I think Arg should not counter Healing Sphere and instead should counter Gloria's Jacks whenever possible, especially non-hearts Jacks. Sending those into the discard goes a small way towards getting rid of her oppressive attack options.