Everyone in this thread seems overly pedantic and abusive towards the OP, but I shouldn't really be surprised since this is the internet after all.
My first character that I got to 50 is a human Trooper and I'm reasonably happy with that choice. However, if given the chance to change his species then I would probably choose a Rattataki. Of course I could just make another Trooper and make them a Rattataki, but then I would be giving up many hours of gameplay for a cosmetic change, something that I'm not going to do.
Certain other games (which I won't mention because the amount of venom people have towards one in particular is unreal) allow race/species changes. I don't think it would be that hard to implement. I'm sure many people would be happy to pay large amounts of credits to be able to change the species of their current characters. There are even in-game lore reasons that you could possibly do this (The Face Merchants quest on Coruscant being an example).
For anyone that says the choices you make should matter, if that's the case then why can you hit escape to get out of conversations, etc?