One of the Spore developers Isn't Happy with the Wii saying it is just two Gamecubes Ducktaped together. Which it is, and from the standpoint of many developers they are having to scale down their visions of next generation gaming for the Wii and use a control scheme which they don't seem to care about. If the development community had of taken the Wiimote to heart and embraced it for what it is then I am sure more fun experiences would be coming to the Wii, but as it stands only first party titles are using the Wiimote effectively.
Developers for this generation seem to be trying to create games that are bigger than what the Wii can handle. This generation is big on Physics, but this is one area that the Wii can't enter and neither can it do truely threaded processing because of it's single CPU. So although the Wii is supposed to be a next gen console, to develop for the Wii is like keeping one foot firmly planted in the last generation. Nintendo clearly doesn't care about anything other than re-imagineing the same games over and over so graphics and CPU power doesn't matter to them, but for the rest of the development community this is a problem.
Incidentally there is a new Paper Mario game coming out for the Wii. Switch from 2D to 3D while playing, er, ok.