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.
Talking about hundreds of hours of dialogue here. Almost definitely off the cards. The implementation would be difficult, too, since at present each class only has two sets of voice recordings based on gender not species. That's a whole lot of re-coding.
I think the best we can hope for is more voice morphs like the helmet echo but maybe more of a raspy morph?