If another person says Sora, I will personally shoot them. =/
And let's see.. A WTF character.. Snake didn't become that to me when I saw that, I just thought in my head "Oh ****, it's Snake! =O And he's in a box! =O", granted, I don't agree with Snake being in brawl for his key differences, but they're making it work, and I probably will be using him every now and then for a fun MGS feel.
I think the biggest WTF character they could add would be like another NES character that few remember. People expect NES characters now, but they don't know which ones to expect, with the wide variety to choose from. It could even be Bucky O'Hare for all we know. (I doubt it, of course, but it was just a random NES character that came to mind.), or Wart even. (Mario bros. 2)