Supergirl is now really viable, especially if they overbuffed the damage, but making her whiff punisher safe is not gonna change her from top20 to top1 for sure.
Based on what we know my bet on the top tier is this:
Black Adam (with the meta shift who knows, but he 1st place is a solid bet)
Catwoman (now she's not broken, but a lot of tools are still there)
Batman (he's doing good everywhere, and his bad match ups got nerfed)
Superman (still very solid, not sure how no ultra dash punch will impact him)
Darkseid (depends on the meta, might be overestimating)
Harley (her only unplayable enemy was Aquaman... she will be in a pretty good spot)
The rest of the cast is pretty balanced except some guys with huge flaws like Joker (who's still playable but still... maining him would be madness in any tournament).
Anyway, some will obviously do better overall and have better mu, my bet for upper mid tier (a tier? a+?):
Scarecrow (was good before... his bad matchups nerfed... profit?)
Supergirl (still has her obvious weakness, but as time passes veterans are learning new stuff, keep an eye on good Supergirls in the next weeks)
Wonder Woman (idk, imho she's strong and very underestimated)
Deadshot (still very good, but if b1 is a lot slower it will be an huge loss imho with f1 being already slower)
With Flash, Green Lantern, Cheetah, Green Arrow, Brainiac, Atrocitus, Aquaman, Black Canary, etc being close.
I don't think this is an accurate prediction cause we got to discover a lot of stuff in the ''mid'' tiers, game is still fresh, but more or less will look like this. Also i'm thinking about reasonable damage changes, feel free to put SG top tier if her combos will do >400. And Superman mid tier if his damage will be lower than it should be.