Few points I'd like to toss in.
Mez is too "all or nothing." If you don't have mez protection and you get held, more often than not, if you don't pop a breakfree, you lose. On the other side, having 5 stacked CMs on you makes a controller totally useless, and when you're not in an arena match, breakfree consumption isn't really much of an issue. I think the concept of mezzing in this game needs a total rework.
Some inspirations should have a cooldown time. Not all, but some.
Make stun act differently than hold as maybe you can move around but not attack (and I don't mean the slow walk you do now)
Reduce the time on holds, but increase their power. Meaning, it takes less to hold someone with mez protection, but it's not the "end all" once they are held because it'll break off sooner.
A lot of buffs/debuff need a look at too. Personally I don't think cm should stack more than one per caster, like bubbles and fortitude. This would also help stalkers a bit in higher end PvP. Forcefield buffs could use a boost, to bring it in line with fortitude (I'll never understand why fortitude gives 30% base defense, which is far more than you get out of bubbles, and slotted with powerboost it's just ridiculous)
Fix Fly. There's no reason why cj/sj should just totally outmatch it. The only thing fly is good for right now is getting away, and really, it's not even good at that, more like taunting jumpers with "You can't get to me." Hover needs to be faster, fly shouldn't slow down as much as it does from surpression, and the ridiculous about of -fly needs to be addressed. I made a fly build on one of my blasters for fun on test, and while I was able to beat some people, for the most part, I didn't stand a chance. The most recent was fighting a jousting bs/regen. It was just a sad attempt at me slowly trying to chase him around while he jousted me. All the technical hate for fly is not forgotten, even when you give it stupid perks like wings. All the fancy graphics in the world do not actually improve fly, so the devs need to stop kidding themselves. Reduce the -fly and give hover/fly some ability to move while fighting. We don't want more -jump, we want less -fly.
I agree with the slow resistance totally outmatching slows. One SB or AB totally outclasses any slow. On the other hand though, I think slows are too powerful. the -recharge builds far too quickly, and should have a reduced cap.
Fix brute fury and fix dominators. The problem with dominators is that they're balanced... but everyone else is too powerful. This just doesn't work.
And my BIGGEST issue at hand is power set balance. Why oh why do energy and electric blasts have to have animation times that are double fire and ice's animation times? Just reduce them already, give these sets a fighting chance in PvP. Energy blast also needs to have it's knockback at least sometimes cut through KB protection, because as of now, it's damage is balanced against this, and no one gets KBed in PvP unless they forget to toggle on acro. This makes it easily the weakest set to PvP with. Also, bring the 'short range heavy hitter' blasts' in line with bitter ice blast. I know ice doens't have the snipe like the other sets do, but the least that fire and energy could get would be more range, and maybe a bit more on the brawl index for those moves. As of now, they're weaker (unless blaze's DoT kicks in) and far shorter on the range scale. I know I'm not the only one who is tired of seeing ice/energy (despite the fact that mine is from issue 0) blasters, with the occasional fire/energy tossed in there. On the same note, give elec blast a heavy hitter and give /ice and /fire some love. /elec is already pretty good, though /energy is just beyond everything else in sheer power, mainly due to power boost.
Also, give dark melee and claws real buildup or at least give soul drain's first tic the highest one so that it does something against one target in PvP. They shouldn't have to pop a ridiculous amount of enrages just to do any decent damage.
Reduce cage time, or allow breakfrees to work against it. even if it's more than one, like TK for mind.
Fix earth control in PvP. the set is practically useless if the target wants it to be. I posted about this on the test board as well, and someone linked to the original thread with videos.
I don't believe that villains get access to strength of wills in Siren's. If they don't, either give it to them, or get rid of it on the heroes side.
Edit: forgot something.
Severely reduce the spawns in PvP zones. People go there to PvP, not have their fights ruined by the million arachnos running around in RV, for example. It also is extremely annoying to run any kind of AoE such as hurricane, force bubble, tk, rad debuffs, etc. Because these draw so much aggro from NPCs, especially force bubble since it's so damn big.