Force Fields - yes, this set could use a 2nd revamp, but it is still stupidly strong for what it does - a single defender can softcap an entire team on just SOs if I recall. I would welcome revisions.
Empathy is fine as is IMO - intentionally ignoring the arguments about debuffs over heals, the set is really not bad or in need of a rebalance.
Regeneration - oh hell yeah, this has become a meme at this point. Anyone arguing against Regen needing retooling has got to be trolling - not that you can't make it work, but they are very aware and I've seen the devs and GMs make jokes about it as well.
Masterminds are slowly getting fixes which I am thankful for. It's a lot of work.
Outside of that, I would vote Poison getting a revamp above Force Fields and even Sonic Resonance above Force Fields. Super Strength's Rage issue is probably a hard problem to solve and might be the reason it hasn't been proliferated yet.