If Ubisoft was a startup company, I'd believe that it would take significantly more resources to add a second gender. But they're not. They have 5 or more studios working on each game and years upon years of assets waiting to be utilized. They've made previous playable Assassin's Creed females; use those models/animations as a basis. A bonus idea would be to use the same people who made those assets and have the experience modifying them to work on creating new female models/animations. A couple of days, max. Ubisoft is too big to give these shitty of excuses.