I don't believe that more content = better game. Thats exactly the kind of attitude that has caused other developers to fail.
For example, SMB2 (Japan) added more levels, more items and more mechanics to SMB but there are very few who would say it is a better game. SMB was, because it was original and innovative.
What Nintendo needs to do is to reimagine each series with Wii controls. MP3 did this the best: while I disagree with the design choices, the game was successfully redone for the Wii. They just didn't use those new ideas enough. Other series that would benefit from Wii reimaginings (but wouldn't benefit much from just a graphical and content upgrade) are Starfox, Kid Icarus, Kirby and an RPG Paper Mario.







