Sure it'd be cool to have new alien races as heroes, but also I think it would be nice if there were more of the ones we already have. It's a bit weird to me having just a single one representing each race while the humans get all sorts of diverse characters.
Not weird that just how the universe has played out. In Star Wars humans started out not just on one planet but many including various subspecies of human. Where as say wookies originate on one planet and very few have a real desire to ever leave it.
Basically its alot like real life where humans outnumber almost every other animal by hundreds if not thousands.
From a game perspective human beings tend to relate better to humans/humaniods hence why humans/twileks/denvarodians and wookiees feel better to play as heros as opposed to say a wampa.
I understand that it makes statistical sense, I just think that it would be more interesting to have, say, a couple of different Wookiees or a couple of different Mon Calamari etc., and I think that in game design you can tweak the statistics a bit in order to have a more fun and diverse set of characters. It's not the fact that there are more humans than anything else, it's that every other race is represented by a single character as if e.g. Bothans can only be sneaky spies and nothing else. It doesn't really bother me, I just think there's some unused potential there.