I laughed at the order of your comments "Ok" "Really" and this one.
They are very similar, the heads themselves are the same, the textures are the only thing that is different. This is to save them time, otherwise ME3 would likely take another year or so to complete. That and the space on the disc needs to be accounted for.
Haha, I was hoping for you to notice that I thought you were going to be confused reading them separately >.<
but yeah, they could of at least replaced the clothing with some Human Armor. =___="" Don't Batarians and Drell have the same Male Human body shape? >A< but what you say is true... it could of taken them longer.
I just hope in ME3 they give more variety on weapons and armor. Same goes for hair cuts
Batarians have the human male and asari have the female body. Drell have their own body shape, slightly more slender; assumedly to make them look more agile (more suitable to being assassins than a larger person). The only real difference between them is the colours, though.