I agree with a fair amount of your points. I agree that Wii, to be cometitive, needs to bump its graphics up to the current standard. The publishers and developers need to be able to port a game across platform without worrying about the graphics, controls is enough to be worried about.
I don't agree with your opinion about the third party support though. I think third parties put out a lot of really good gems on the Wii, but nobody bought them. I was listening to a podcast and they said that the first months sales of Madworld was around 17,000 units. I bought Madworld and I thought it was a flawed but good game. It had amazing humor, which I think was much better than Bulletstorm's humor. Muramasa, House of the Dead: Overkill (funny as hell), and Arc Rise Fantasia were all games that I bought and loved. You mentioned Burnout, but did you play ExciteBots? I know that they aren't exactly the same, but Excitebots was so much fun to play. It was especially fun to play with a few friends.
In the end, it was sales. Good, hardcore games came out for the Wii. But, alas, nobody bought them. At least not with the same numbers as those who were buying Wii Sports Active.