If they are going to be added in with a full expansion (which has a much higher budget) then maybe they could hire some more voice actors for races like trandoshan etc, which speak basic but with a strong accent. I think that is as far away from human we are going to get.
Lucasarts have already said NO to wookies as jedi/sith and the "Yoda race" as playable in the past to other developers, so I highly doubt we will ever see them.
They've actually recently introduced more Wookiee Jedi characters into the Star Wars universe. BioWare have yet to ask if they could allow players to create Wookiee Jedis so there's still a chance, plus it would be non-canon. In addition Star Wars Galaxies allowed you to create Wookiee Jedi.
I think Yoda's species would be more acceptable as a companion since little of their background would have to be revealed, even through dialogue.