IAWTP, so, SO much! :) You're right in that genderswap isn't inherently OOC; I often wonder what I would be like, for example, as a man. I have to think that I'd be slightly different because of the experiences engendered (no pun intended) by my gender, but the essential genes are the same.

Just because Leonard McCoy is a Lena in some story or other doesn't mean she can't be as cantankerous as her male counterpart; perhaps for different reasons, yes, but I believe that genderswapped characters are the same in all the ways that matter to readers.