Certain things have already unjustly been nerfed. Correct me if I'm wrong, but Sinestro had a couple strings (B1-3 for example) that were safe on block, which was perfectly fine. He's a low damage character, and since the day one patch, none of his strings are safe on block. This ruins his up close game against any player worth half their salt (pun optional).
Hawkgirl, before the day one patch, could convert her D1 into her Wing Evade xx 3. She is a pretty low damage character as well, and something like this could make her better (not greatly so, but then again, why was it such a problem in the first place?), but it was removed. Other characters have far more punishing moves than Hawkgirl that remain in the game.
I don't see the reasoning in either case to nerf those characters, but they were. I'm not a developer, so I can't really judge what should and shouldn't be tweaked, but I personally feel those adjustments in particular were unnecessary.