Pretty happy to see such a tournament being run. Also happy with suggested changes to be tested. Since I agree with 90% of them 
I finally got around to post Blue vs. Black nerf test session report from February, so a bit of an opinion on changes to test.
Black Starter:
I suggest to also nerf Graveyard to break when it holds 3 units instead of 4.
Curbing Haunt to 1g sounds interesting, as this nerf also hits Graveyard and Sacrifice effects as collateral.
Demonology:
Dark Pact to deal 1 damage to Vandy instead of 2
Nerf Vandy’s midband to levels 4-5; Maxband to 6. Still not sure if cutting Resist is correct, but it’s such a red flag for everyone else, so try it, whatever.
Metamorphosis: Remove Readiness instead of Invisibility. I think Metamorph is too much of a different/weak card without Invis. The point of it is to go all-in on heroes; Without Invisibility it loses this design intention. Testing absence of Invisilibity could be interesting from the point of view “How much of a nerf is too much”, but I’m afraid it would all but kill the card from design space standpoint. If you believe cutting Readiness alone is not good enough, maybe cut one of +1/+1 tokens as well. But keep Invis.
Disease:
Orpal Midband to be 4-6, Maxband at 7.
Blue Starter:
I think letting Building Inspector straight up discount controller’s buildings 1/turn is way more elegant.
Law:
Don’t like suggested Jurisdiction change. Clunky. Barely changes anything at all. I like tucking Lawful Search effect on this card instead. Very elegant, and powerful. Full text would be “Look at opponents hand or discard pile. Then play any non-ultimate spell from your codex, paying it’s cost and discarding it.”
Peace:
Drill Sergeant NO NO NO. You lose Hallucination / Dreamscape combo with this change. Just limit rune moving ability to 2/turn, same as Blooming Ancient.
Truth:
I’d suggest discounting Quince’s midband ability to 1g or — if you are feeling bold — making Mirrors 0/2s.
I like everything else in the list except for a few minor odds and ends here and there, like KotC Forecast at 2 is too much with Time Spiral and Tinkerer changes, Regular Sized Rhino is now very sad when compared to Oversized one, don’t understand +1 HP on Predator, agree with Bomber on 2g Rich Earth, etc…