Why do developers do things backwards? Why do they target games for 2 consoles that are so far behind the leading console in sales? Wouldn't you make more $$$ if you created the game and targeted it for the Wii? and then port it to the other consoles?
My guess is that developers are having the same problem they have always had. They struggle to make the game play fun. Few games have had great fun game play on the 360 or PS3. They sell games by having pretty pictures, and meaning less features, (like the more amazing AI you've ever seen, yet no AI in any game ever produced has been worth a crap).
It is a much more difficult task to create a fun game. So developer default to the "easiest to impress" platform.
The Wii is out selling the 360 and PS3 by a large margin, it has the largest user base of any of the current gen consoles. Yet it is an after thought for most developers.
I bet the game developers are just happy that the publishers are ignorant of marketing and business, so they don't have to make the games fun, they can just keep trying to out geek each other.
Would I like the Wii to have HD graphics, crazy poly counts, life like AI, ect....YES!!!!, but not at the expense of Fun, or the game play....Give me fun every time.