Capcom producer Yoshinori Ono recently spoke to Xbox 360 Achievements about the exclusive characters in Street Fighter x Tekken. After securing exclusive characters for the Playstation version, Ono reached out to Microsoft for a few more.
"We do have the exclusive characters for the Sony platform. We have Cole (from inFamous), the two Sony cats, Kuro and Toro. But basically for the Xbox 360, we were in discussions with them (Microsoft) for which character to put in as an exclusive, but we weren't able to decide on a character because of differences in timing and things like that," Ono explained. "It's something we wish could have happened. It's just too bad, basically."
Ono was then asked which characters he would have liked in the game. "In terms of characters we wish we could have put in the game, Master Chief or Marcus Fenix from Gears of War would have been really cool, but it was just really difficult," he replied.
Though as unfortunate as it seems that both Master Chief and Marcus Fenix won't be present in the final game. Xbox 360 fans may take solace in that Capcom are infamous with their DLC and expansions, one of which may even include the two characters sometime in the future.
Source: Xbox 360 Achievements