The fact is that the HD consoles are at their peak now (or close to it). Wii is not. People seem to be forgetting that the HD consoles will eventually go through massive declines as well, they are not invincible. As Wii has shown, no console is invinsible to eventual decline. The redesigns have prolonged this decline, but they can only do so for so long. As The Source I believe said, Wii having the highest, most rapid peak, leads to it having the most rapid decline as well.
On the topic of DKC, it won't be as influencial as NSMB Wii in lifting hardware, but it will certainly make an impact. Plus Goldeneye, Epic Mickey, Wii Party, and Kirby can pick up that extra slack. Nintendo basically has it in the bag against Sony. If PS3 can't even outsell Wii at its low point in the slow summer months with no sinigifanct releases, then it certainly won't during the holidays, which is a strong time for Nintendo hardware. As for 360, I think people are puting way too much hope in Kinect. The hardware may be neat, but it doesn't appear to have any decent games worth buying it for. Halo Reach will do more than Kinect. At the end of the day, people buy hardware for the GAMES. Nintendo's lineup this holiday looks to be the strongest, so I think it'll get the most sales.