The news of the Tekken /Street Fighter crossover games sure has pleasantly surprised fighting game fans. For the uninitiated, Capcom and Namco Bandai are each creating their own crossover fighting game titled Street Fighter X Tekken and Tekken X Street Fighter respectively. They are not joining forces to create one game. It's pretty much the same as Capcom did with Capcom VS SNK, except SNK did not create their own version of the crossover. You may remember that while SNK characters were present, the characters were changed to fit the Street Fighter gameplay and it still felt like a Street Fighter game.
Still, at least both games were 2D fighters and shared some similarity. On the other hand, Tekken and Street Fighter are two very different fighting games, even if you put Street Fighter IV into the equation. So while it's a cool announcement, I was definitely surprised and wonder how each game will turn out. While Street Fighter IV is great, I think that Tekken X Street Fighter might turn out better of the two games.
Another interesting factor is the commercial viability of both games. Fans will see them as separate games, but are they willing to buy both? Will the average consumer know the games are any different? Going by the slight change in the title name, I don't think they will. Releasing two games might bring down sales for both. It will be interesting to see how it turns out.
Two fighters which would be a perfect crossover, in my humble opinion, would be a Tekken/Virtua Fighter game. Dead or Alive would also be a good fit with either, but is still Xbox exclusive. Still, if these games sell well, another crossover could happen.