If the argument is that programmers or artists would rather work on a game that stretches their abilities to the max -- and allows them to create the greatest works possible (like Doom, or Command & Conquer, or... I assume... Mario 64, or LoZ:OOT), that's fair. In fact, that's something they can be proud of.
However, this argument (like so many others) really boils down to a belief that, somehow, graphics are exclusively what makes games good. A stupid, stupid argument.
Programming is a complicated business, and while making wonderful graphics is tough, there are plenty of other design challenges. Like making an interesting story. Or an easy-to-pick-up interface that eventually leads to deep controls. Or fun gameplay. The Wii affords a lot of things for the ambitious programmer/designer to sink his teeth into.
Not only that, but with its motion controls (however well they've been implemented thus far), programmers have the opportunity to push game design to places its never yet been. It would be like working on the 1st gen of 3d titles. It's a brave new world, and if you were really looking to stretch your craft and create something unique, Wii would be the place to do it.
Finally... is it really the implementers that get the decision about what system they design games for? I would imagine that it's actually the bosses and/or investors who make those kinds of calls, and that they're ultimately not about artistic fulfillment, but trying to profit so that they don't go out of business. The fact that so many third party developers are in financial jeopardy seems to indicate that, so far, they've been making some very bad choices...
