Copy&pasting what I wrote in another thread, since everyone is ignoring it there, and it's actually more on-topic here:
First of all, look at the Wii's software sales.
See all the third party million sellers? There are 8 now, with 1 more arriving next week, and 2 almost certain to reach the magic number in a month or two. This means third parties are selling well on the Wii.
Next, look at the list of upcoming games.
See all the third party games? Certainly not all will end up great, but at least King's Story, Odoro Muramasa Youtouden, Opoona, Battle of the Bands, Monster Lab, Boom Blox, Tales of Symphonia, Fragile, Mushroom Men, Crystal Chronicles, De Blob, and Deadly Creatures are serious exclusive efforts by at the very least decent development teams. They're not even nearly all AAA, but there's not a single piece of shovelware amongst them. I don't think Zack&Wiki or No More Heroes were even announced this time last year, so we can expect several more titles that we haven't heard of yet. That's not even getting into multiplats like Alone in the Dark, Spore, Rock Band, and Street Fighter 4, or the entire Wii Ware service.
In other words, we already know of many times more promising third party exclusives and multiplats in March than what came out in all of 2007. This means third parties are significantly increasing their support for the Wii.
Now you've probably noticed that most of the exclusives aren't exactly big names. That's because big sequels to popular franchises, probably what most people refer to as AAA games, take a long time to develop. The Wii's status as this gen's best selling console only became apparent during the last year or so, and the best dev teams of most publishers are still working on various projects for the HD consoles that are too far in production to suddenly port over.
Yes, we've been saying this for quite a while, but it hasn't suddenly stopped being true. So far Monster Hunter 3 and Fatal Frame 4 have jumped over to being Wii exclusives, and don't expect the trend to suddenly change for no reason at all. This means the Wii is starting to get big AAA games as well. Just slowly as expected...
tl;dr: third party games are selling well, the Wii is getting many times more 80+ games in 08 than last year, and AAA titles are starting to jump over as well.
