I think nerfing trait kills but still allowing for any other chipout would be somewhat silly. If Crow wasn't chipping your last 2% with trait, or Ivy, or Atrocitus, or Darkseid, or Swamp Thing, or Black Adam (and so on), it would just be a meter burned move to do the same. Granted, I don't think Crow's trait should have ANY affect while you are hurting him. I think that if you manage to land a long combo that disables trait and Oki him, you deserve a comeback. Chipout? Sure. Kamikaze wins? Pretty cheesey.
I think bigger gaps for Supergirl would be fantastic. It would encourage smarter play. Her lasers are fine, she should just have less access to them. Like... A lot less. Throwing out a laser in neutral should feel like coming off of a valuable resource. It would keep them as a counter zoning tool and would make laserwalk a bigger cash out.
Catwoman would be fine if her hurtbox issues were fixed. Her B3 is not ok. Her backdash is also a little nuts. I don't think her plus frames need nerfing if those happen.
Black Adam's plus frames are kinda ridiculous, there's no reason to have something be plus all the way up into the 20s. That's some prepatch Lao BS. His MB divekick should also be minus from every height and maybe startup just a few frames slower. Possibly make black magic more minus? I think a fullscreen combo starter should warrant significant risk.
Aside from all that, maybe add a little more recovery to Hellboy's gun in the style of Red Hood's gun. It's a little too good right now.