It's 2014. You are a large studio working on a triple-A game. These excuses are no longer good enough.
Talking about female characters as something you need to add to the game as a sort of afterthought, as though a large chunk of gamers should be happy that they're being given token representation, is bad enough. That you then just don't bother at all is pretty ridiculous.
After all, it's not like there aren't other games that have female avatars. There were even female models in multiplayer for Assassin's Creed III and IV. Yes, the issue isn't easily solved just by throwing more money and developers at the problem, but it should have never been a problem in the first place. Having female avatars is something that should have been a core part of the game from the start, not some "nice-to-have" feature that you can cut when you run out of time.
The "reality of production" excuse just doesn't wash any more. What you're really saying is "women weren't important enough to be a core feature, and aren't important enough to push back our release so we can include them".
Assassin's Creed Unity's four-player co-op will not offer female assassins due to the pressures of production work, Ubisoft creative director Alex Amancio told Polygon during a recent interview. Amancio said that though female assassins were planned for the game, Ubisoft ran into "the reality of production." "It's double the animations, it's double the voices, all that stuff and double the visual assets," Amancio said. "Especially because we have customizable assassins. It was really a lot of extra production work."