Comparing console versions of arcade games generally does them a horrible disservice, especially VF. VF was the flagship title of some seriously powerful and specialized hardware (the Model series), while during that time Tekken was restricted to increasingly tweaked variations on the PS1.
The main problem with a crossover is the drastically differing systems. Control is a relatively minor quibble as long as all characters can, for the most part, perform the same actions, but I can't really think of any way to mesh things like okizeme, evades, throw escapes, clashes, etc.. They might just go the "groove" route. With either system, though, the Tekken characters will probably have an advantage.