As far as AT overhauls go, I think a good number of people will easily put Masterminds and Sentinels at the top of the list, at least above controllers, dominators, and kheldians. Dominators may just need number tweaks after the previous overhaul if they are still underperforming though so it might be low hanging fruit if they track play results.
Poison, Traps, and Force Fields need looking at also. Sonic Resonance could use some love, as well as Sonic Attack and maybe some slight changes to Assault Rifle.
Porting sets via (hopefully) smaller overhauls are still there like Super Strength, Stone Armor, Energy Armor, Stone Melee, etc.