Publishers had cold feet when next gen was announced.
We saw this when Japan decided to exit consoles, and the West was shoveling cross-gen titles onto PS4/XBO.
Because of that, new games like Ass Creed probably weren't given the proper time and money to have a nice frame rate because Publishers still had theirs eyes on PS3/360.
Now that next gen consoles are actually a success and PS3/360 are winding down, Publishers will take them serious again.