Minecraft needs a friends list where you can add people by their username. In that you could add a voice chatting system or something. Also, you should be able to change your username because I do not like mine and I cannot change it. So, Those are my suggestions. + =
Steam would **** it up >.<.
What do you mean what's wrong with one?
I sympathize that you are unhappy with your player names, but I feel you should have thought about it when creating your account.
If it's an big enough issue, you should buy a new account for Minecraft. A monetary penalty would be the only feasible way to prevent abuse.