My guess is nobody. Not that nobody needs it. The devs seem busy with other issues, and the characters who the forum thinks need buffing have been that way for ages anyway.
I'm with the majority - I don't think any character particularly needs nerfing, and the blowback from the last one was so bad I hope they won't nerf anyone any time soon. Honestly, I don't think we've had a needed nerf since X-Force Wolverine. The OML nerf was more or less unnecessary, though I suppose they could have nerfed his "less than max covered" usefulness since they clearly changed their philosophy there.
I'm with pretty much everyone else on buffs. They should also make some tweaks to the older 3*s like the Hulk - his red is particularly useless and his green is underwhelming. But I don't expect a lot of action in the 3* tier.