They do have a lot of good games coming out this year so far. I know I will probably not have all the ones I want by the end of the year. Zelda while I used to love it just does not do it for me anymore. So in that way yea I can see it not being a huge system seller., but many people do still love it.
I think or well I hope Xmas comes as a mixed bag of games. I assume we will have Wii Vit Sensor by then. I assume we have have some neat games to try with it too. Is it a system seller though? maybe maybe not we will not know till then. I also assume we will have a few more "core" games other than Zelda. Maybe Kirby or something along those lines to go with it. Do not forget we do have some more 3rd party games coming out that look promising. To bad we do not have all the release dates yet.
All and all I think Ninty will do just fine with the Wii and D.S. all year. Guess we shall see how it goes.