Juan Gril has what he terms a 'rallying cry' up on Gamasutra: the topic is innovation, specifically in relation to the casual games market (but I think this discussion applies on a much broader level to the industry as a whole, as evidenced by slews of blog posts and articles bitching about the topic). He draws a line between games that use incremental innovation - that would be the various incarnations of the match 3 formula, for instance - and games that have totally unique mechanics. Going a step further, he compares games from 1984 and 2006, finding that on his list, the 2006 variety lags far behind the older generation in terms of turning out unique mechanics, relying much more heavily on the 'incremental innovation' formula.
I'm sure a lot of you have similar stories to this one: New Publisher Division, first six months: "We need to differentiate ourselves! Let's create radically innovative titles. Let's show the other guys how it's done!" A year later, of the 12 titles released, only one is a hit. Another two have been fairly successful, but with flaws.
Sales steps in: "We're not selling squat!" A coup d'etat ensues. Next year's portfolio is 50% clones, and 50% minor incremental innovations. Sales go up, but churn is high because players lose interest. We need to understand and plan this better. We need to realise that incremental innovation is what most players feel comfortable with. But radical innovation brings new players and renews the interest of existing ones who are done with their favourite genre.
The problem is in striking that healthy balance between "Oh god, not another [Bejeweled/Final Fantasy/insert game of your choice here]rip off" and investing in 'different' games that wind up flopping (see: Okami). That line is obviously going to be different for casual developers vs. studios making games for a 'hardcore' audience, but there's got to be a healthy balance somewhere. Innovation in Casual Games: A Rallying Cry