There are a lot of alien models already from Jabba's palace and the Catina :
Gamorean , piggys
Walrusman ( don't know their real species name)
and that weird "two in one" alien + those used mainly for the Vulkar thugs ( can't rember the name )
But it wouldn't hurt to have more of them , and mainly in your party .
Its just very dull that in both games you don't have the choice to be an alien yourself or to have more of them in your party .
MORE ALIEN types please