The worst I've encountered, though, was FF!Sue and Scarlet Witch. Laaaawdy. I'd never faced SW before so I only had a vague idea what to expect. Now I'm terrified of her, esp. if I see her in combination with IW again. It was like a nonstop debuff/healing/shield party and nothing I did made the least bit of difference.
Also had my first run-in with Quicksilver (I'm still a newb, remember). Man, he's an annoying little twerp, isn't he?
Strange is making a few appearances as well. Still can't take a punch, but he's a lot more dangerous to face now. Freaking BANE, ugh. I haven't noticed his new shield passive in play yet.
Still cracking up at HT's Nova Blast, because it has yet to accomplish anything but being a flashy suicide tactic. Does come in handy, though, when my Torch and the opponent's Torch have been hurling fire at each other and healing back and forth for ten minutes, then the other Torch apparently decides to just call it quits.