removing the game that's synonymous with the system makes little sense to me.
Actually, it makes perfect sense. A lot of casual gamers who picked up the Wii played Wii Sports and absolutely nothing else, so they never felt the need to actually go out and buy any other game. I'm sure Nintendo was really frustrated at that, because on one hand they made a really great entertainment package that consumers saw a lot of value in, but on the other, it was a little too complete, because the casual gamers had all that they wanted.
With Mario Kart, they're going to get a lot of people who buy that, play Mario Kart, and then say "Well, what about that sports thing everyone was going on about?"
The danger, of course, is the possibility that because Wii Sports isn't included, people won't buy the system. Once again, this is casual gamers we're talking about. When my 2nd daughter was being born, we had to send our oldest to my parents for 3 or 4 days. So they wouldn't get bored, I also took over my Wii and about 10 games, all the casual games I had (Just Dance, Wii Party, etc..). The only games that were played were Just Dance Kids (my daughter) and Wii Sports (my parents and my kid). My parents even asked to keep the Wii for another week so they could play more Wii Sports.