Yoda's race will never be playable. Nor should it. Respect the IP. Part of what makes certain characters or things special is their mystery. If you ruin the mystery then those things become less special, less unique.
Plus, playable races have to fit the parameters set by BW for SWTOR, regarding physical size.
No one necessarily said Yoda's race had to be a playable one. The race could be included, however, as part of some expansion storyline. That, in fact, could add to the mystery a bit, by expanding said mystery, giving tantalizing hints, etc.. That, in fact, would be "respecting the IP," at least by some people's viewpoint. Personally I'm not one of those that are terribly interested in Yoda or his species -- but many fans are, so at least exploring and/or considering options seems like a sensible thing to do.