We recently spoke to Tomoaki Ayano, Producer at Capcom Japan, and talked to him about how characters were picked for Street Fighter X Tekken. Like presidential politics, it's basically a popularity contest.
"The Street Fighter and Tekken universes have hundreds of characters. It's always a tough thing to choose which ones you're going to put in the game, obviously not everyone isn't going to be happy," Ayano said. "We do our best to listen to fans and see which ones are the most popular."
Check out the rest of the interview in the video below: