I believe the Wii will do extremely well. Everyone I know is getting one (that's why I'm NOT getting one, at least not yet =P). The trick here is innovation and money.
It's been a while since the gaming world has seen any console upgrade other than BETTER GRAPHICS (YAY!), FASTER SPEED (AWESOME!), and MORE DISK SPACE (WOOHOO!). While this "type" of controller has been attempted in the past (an independent handheld game by Microsoft no less...I'd be surprised if anyone else remembers that because it was a LOOOONG time ago), the difference between then and Now is how many games are going to utilize the controller.
While this is cool and all, the most important factor on everybody's mind--not just the average consumer's--is, "How much will it cost me?" Nintendo...wins.
The average consumers are going to jump on this newfangled technology especially because of its cheaper price.
If Nintendo keeps up the pace and advertises the Wii correctly, I'm absolutely sure it will come out on top this time.
While I commend Sony for creating all the technology for the PS3, I won't be buying one until it gets way cheaper. And I'm a PS2 junkie... I'd just rather upgrade my PC with $600 than buy a PS3 for $600 that I'm only going to play maybe 2 games on (Metal Gear Solid 4 and any Final Fantasy game that comes along).
Also, can anyone say, THE TWILIGHT PRINCESS?! YEEEEEEEEEEEAAAAAAAAAAHHHHHHHHHHH!!!!!!!!!
EDIT 1: Whoops! As for the original question...it all depends on game developers. If we want it, we will make it happen.
EDIT 2: And it's around that time when the people who used to LOVE adventure games are now regular video game consumers. I'm sure there's a better chance now than later.