The notion of innovation as a necessity to a game being great is flawed down to its roots. Sure, we've seen great games do things totally out-of-the-box, a la Mario 64, Resident Evil 4, and Pokemon...but really, you look at series like Suikoden, Silent Hill, and Call of Duty, which either don't innovate at all or just add one aspect to an already-proven method.
Then you look at other games like Brain Age, Ultimate Spider-Man and Gun Valkyrie which are truly unique games, but just plain suck, and you have to wonder why "innovation" is even really considered a must in determining the quality of a game.
Skies of Arcadia was a generally non-innovative RPG. Gears of War was RE4...but with bigger guns and a 4v4 online setup that is SOOOOOOOOOO 2001. New Super Mario Bros. Metal Gear Solid 2. Legend of Zelda: A Link to the Past. Devil May Cry. Forza Motorsport. Bioshock. Half Life 2.
How many of these games were innovative? How many were great?
Bam. I win.