Assassins Creed 2 and Brotherhood had little bits of tits and ass making them wildly popular among 15-16 year olds. But then Witcher 2, GTA V etc upped the amount of sexuality while Ass Creed actually reduced it to make it more palatable to a wider audience. Problem is, they had already fired most of the narrative guys who'd made 1 a hit without tits, and the new writers couldn't even manage safe horny. And along the way the franchise lost its identity and became a generic open world game like Far Cry/Watch Dogs except with swords instead of guns.