Tekken X SF wouldnt be the same as SF x Tekken simply because two different developers and the mechanics will be different since Tekken isnt the same as SF. I'm pretty sure at this point, Tekken X SF will become more popular but only if they go that route.
Doesnt seem like Capcom's gonna invest on it though, such a shame too cause I wanted to play SF X Tekken on PC ;(.
I realise it wouldn't actually be the same. But people are going to see the name and associate it with SF x Tekken and all the fiasco with on-disk DLC and I'd imagine that will put them off.