I believe we've already heard the final word on the status of the Wii: It IS competing in the same league as the PS3 and XBox 360. Take a look at the link below:
The source doesn't separate out the handheld and console markets, but considering Nintendo's equally strong performance on both fronts, I think the end conclusion holds. The relevant passage is this: “The claims are backed up by IDG figures which reveal that the last few years of industry expansion have been driven almost exclusively by Nintendo formats. Without Wii and DS hardware and software sales, the overall international market actually declined by seven per cent last year”. Given the ever-increasing cost of developing HD games (see: $100 million for GTA IV), a sizable reduction in market size such as this would come as a double whammy for most developers of "core" games, meaning the industry may actually be at the brink of disaster right now. Basically, if you accept that the Wii is not in the same league as the PS3 and XBox 360, then you must also discount their share of the pie. If you discount their share of the pie, suddenly the whole pie has gotten smaller, and the developers much hungrier. In other words, it would mean the "core" gaming market is actually shrinking, and courting a second industry crash.
Super World Cup Fighter II: Championship 2010 Edition