Street Fighter X Tekken released on March 6, 2012, meaning Namco Bandai has been answering so-where-the-hell-is-it questions about Tekken X Street Fighter since March 7, 2012. Five games under the Tekken brand have appeared since, raising offhand speculation about TxSF's priority.
Street Fighter's star producer certainly didn't help things much when he joked that the game wouldn't get here until 2018. And as far back as 2011, Yoshinori Ono said the two projects were on independent timetables, and that back then, Namco hadn't started Tekken X Street Fighter yet.
Well, hold on, says Katsuhiro Harada, the public face of Tekken development, they are in fact still working on the game.
"The game is still in development," he told Siliconera, "so you don't need to worry about that." There are several reasons Namco Bandai hasn't released the game, much less announced a date for it: Street Fighter X Tekken "still had updates until recently," Harada told Siliconera. Further "One interesting thing we've seen with that title when it came out was that it's not quite what we expected."
Harada elaborated, saying that it seemed to have created a new community centered around fighting gamers who weren't playing either Street Fighter or Tekken up to that point. "Rather than throw out our title right away while those people are still interested in [Street Fighter X Tekken] we are looking for the right time because we are still developing [Tekken X Street Fighter]."
Fair enough. Siliconera has more at the link.
Yes, Tekken X Street Fighter Is Still In Development [Siliconera]