They're more or less opposites. Drake used to be insanely good in 2v2/FFA (he is still pretty good in both), while being pretty mediocre in 1v1. Kat on the other hand has always been god tier for 1v1 and pretty mediocre for 2v2/FFA
Kat isnt anywhere near OP in FFA or 2v2, its just 1v1 where she's a problem.
Actually she is a problem in all modes. 2v2 is ALMOST just as bad as 1v1. FFA shes a little better then average because her Level 2 is easily able to get at least 2 kills depending on stage and her gravity is capable of linking multiple people if close enough. So if a Raiden and Heihachi are fighting she can get both and combo both.
Kat is a character who builds AP like a god and has easy AP burst combo's. She's easily a big thereat in FFA if you actually take the time to think about her moves, strategies, etc.
My own personal theme song! http://www.youtube.com/watch?v=fL0nWoHG11Y
Lol, people getting beat the f up by Kat players and come here to complain. Kat is so easy to punish, and you will not win in FFA or 2v2 if there's at least one good player against you, shes only op against people that know how to block, dodge, and grab. You should really try blocking and before coming here to complain. Disclaimer: I am a noob, but i know the basics well enough to know that Kat is really easy to punish.