No defintely don't remove the breed entirely. :cry: I have two MaineCoon-Snow Shoe mixes in real life. One who looks very much like a MaineCoon cat too and not being able to have him properly represented in game would be terrible. I know I could just make him a mixed breed but it just wouldn't feel the same.
But I have often wondered the same thing. I mean yes, I get why the second part of the name wouldn't be allowed alone, but in this case... it's the name of a cat breed...