Put in Sisters of Battle as a functional equivalent of Space Marines. Problem solved. Also, please note that I said "functional equivalent", meaning that I know they are different lore-wise, but are generally on the same side and have roughly the same stats in TT, so it could be used as a workaround for the male-only SM problem.
If there was something to ***** about, then it might as well be the lack of female Chosen in Warhammer Online. The official response was that it wasn't in line with the lore, but the problem is that it IS in line with the lore. Heck, I have a Warhammer book containing a female Chosen (the first Gotrek & Felix book), so it's pretty much completely by the lore.
I may come across as pedantic here, sinc eI do agree with you, but:
SoB are not equals of marines. Oh, they may be TT, but that's because it has to be balanced. TT does not reflect the actual "truth" of the universe. Marines are a lot more powerful in the fluff than they are in the actual game. In that respect, it wouldn't work.
Also, Gortrek and Felix, and all other Black Library Books out there, are actually not official fluff. So even if there IS a female chosen in there, it doesn't mean anything, if we want to be pedantic. That said, I don't remember reading any good reason why all Chosen should be male in the army books, so...
Why oh why does Space Marines have to be the big thign in everything 40k related? Honestly, they are the most bland characters in the universe. Why can't we have an MMO that is centered around inquisitors. IMO, that makes much more sense for a MMO.