Rules: Choose a character to nerf and a character to buff. State why for both.
Nerf: Sly. I was going to say Kratos due to his uncanny ability to seemingly lock onto any target within a 10 foot range making most combat quite ridiculous with someone who knows what they're doing, but Sly's probably a smarter choice, the real reason is his invisiblility that is near unlimited. It's not impossible to see him but given the fact it can be used quite liberally and continuously, it's quite a cheap tactic.
Simply put, let him have a max duration for invisibility of 3 or so seconds so as to not completely ruin the game.
Buff: Sir Dan. He's pretty slow. He isn't as much fun to play as he should be, and his AP builds up slowly. His supers need....some help. They need to last longer. He needs some love to feel a little less....wonky.
You can air dodge out of s s ups upt r2 before up t, if you do two up square it's a little better; if they air dodge they still get hit with r2 after upt, but if they jump after second ups upt will miss. Not reliable at all against good players. Sir Dan is still one of the worst characters because of his supers, despite good ap gain and good presure with plague head and charge.