For me Ubisoft's most candid attempt at this is with AC3, a mixed bag game, but I applaud Ubisoft Montreal for trying out a lot of stuffs. Following right up the charming, charismatic Ezio with a polar opposite protagonist (i.e, Connor) is quite a bold move. Then replacing the city setting with American colonies which offers less stealth (also majorly different from previous game) and focus more on combat is another. Then you have the conflicting idea between Templars and Assassins, the first half where you play as Hatham. Black Flag and Origins seem to be following the same route as AC3, by trying to switch things up with RPG elements and naval combats, but this was done under pressure (AC:BF was made because of lukewarm reception from AC3 while AC Origins was heavily affected by the distratrous launch of Unity and Syndicate's mediocrity) so I find AC3 to be the Ubisoft's best and most candid attempt at innovating the series.