It's all a matter of taste, but personally I feel that innovation is not required for a game to be good. Though very few games can pull off being a great game without some innovation, a lot of this depends on whether you're reviewing from an experience point of view (you're only concerned with the experience you have while playing the game) or a craft point of view (how well crafted is the game?).
Metacritic is a great site that collects various reviews from major publications. The game that inspired the deep and profound question that is the subject of today's post is
Ratchet and Clank Future: Tools of Destruction. Most reviewers seem to think this game is fantastic despite its lack of innovation, while Gamespot thinks it is a mediocre game. Now, I realize that 75 isn't really that bad of a score from the stingy folks at Gamespot. But the average gamer (whatever that is), I suspect, will finish a maximum of about 24 titles a year, so just considering this year, if you only owned a PS3, you wouldn't even be giving this game a glance. Now, obviously not everyone plays every genre, etc., but you get my drift: If there were a top 25 PS3 games list this year, R&CF would not be one of them.
I haven't played the game, so I can't put my opinion in one way or the other about the game, and I must mention that I find GS's 75 way more palatable than the 100s from Gamepro and GameTap, but the general consensus seems to be that innovation isn't really that important. Or, coming back to my original analysis, that most publications review the experience, while Gamespot reviews the craft of gamemakery (I submit their complaints about the story in R&CF as Exhibit A. Will they also rip apart the story for Mario Galaxy?).
What do you think? How important is innovation when you think about playing a game? What are your favourite games that don't provide a single ounce of innovation?