All I can say is that everyone I know bought a Wii in Europe as the family console, for fun with their younger kids (and I'm in that bracket, too) and that they never, ever buy any mature games.
Personally, I suspect that beyond the hardcore Nintendo fans, who it must be understood only make up a fraction of the Wii install base, the majority of the demographic owning the Wii has zero interest in such titles as you describe.
They want more Wii Sports, Resort, party games, etc. and hence the sales of Dance and the like.
I know a lot of Wii owners who are hardcore struggle to accept this, but the reality (so far as I can see) is the larger install base just isn't interested in those types of experiences on the Wii (for sure in Others) and as a result you're only going to see fair to occasionally decent performance for such titles - and I doubt any hardcore mature title will get near the sales of the fun family games on the Wii or their counterparts on PS3/360.
Try to be reasonable... its easier than you think...
