More than anything, I just wish they stopped making AC games and moved on to a new IP. I've never found a franchise so bland, repetitive, and easy (way too easy) while still believing that the core ideas of a good game are tucked away in there. It's really a shame considering what AC came from. Feudal Japan, Egypt, whatever... they all sound great, but I just know trying to experience that period through AC would be a grind fest. I can't take any more of the same mission design, the same button-mashing near-invulnerability, the same unrefined movement controls (there are little things that need to be tweaked and have never been addressed... c'mon Ubisoft).
Prince of Persia, you are missed.
They'll probably stop cranking them out when AC stops ranking in the top 3 selling games every year.
It's kind of hard to say 'Let's just walk away from these hundreds of millions of dollars'.
In Ubi's defense, it hasn't really stopped them from doing new things.
They did just launch Watch Dogs, a brand new IP, they're still working on The Divison, they're finally bringing back Rainbow Six, and they've completely rejuvenated the Far Cry series with a new vibe/direction. Hard to begrudge them a consistent stream of insane income, when they're using at least some of it to do all that.
Even harder when you consider, once upon a time, Assassin's Creed WAS one of those crazy, 'are you serious, you want to do WHAT?!' ideas. It took a lot of faith and even more balls for Ubisoft to put the money and marketing that they did behind a project that weird and ambitious.