Where do people get the idea that it's cheaper to develop on Wii games? Programmers cost what they cost, and to try and build a game that provides an appropriate amount of depth of gameplay and looks somewhat decent on a significantly weaker platform would suggest it might take more effort to try and make a good Wii game.
Sure there's a lot of tripe out there for the Wii, but look at some of the highly acclaimed games developed for the console like Madworld and World of Goo and how they ended up selling and it gets easy to understand the lack of motivation 3rd party developers have to create games for the platform. Even worse, go to a store and observe who is buying games and how they buy - you'll see a mom picking up several boxes, seeing 15-party games vs. 12-party games and thinking they're getting a better deal. Look at how a game like Carnival Games sold as an example. It's got to be depressing for a game company to try and think about what great game they can build when they have Carnival Games as the model of how a game without Mario can sell well on the console.
People use Monster Hunter as an example of a good game that sold well - however what they seem to miss is that the game was bundled with the console. A special version of the console no less. Any game should hit 1mil in sales being packaged with the Wii.
I'm not saying it's impossible, but without Mario, it sure looks bleak.
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