To me, graphics are the biggest part of immersion in a gameplay experience.
I've always been a Nintendo fan, but I look down on them for their inability to compete with the latest consoles.
And graphics aren't the only thing the Wii can't compete with, unfortunately. It falls short of all technical aspects featured in the PS3 and Xbox 360. For now, you're not seeing much difference, but, in 2-4 years, the PS3 and 360 will be doing much greater things, and the Wii just won't compare.
It's very disappointing.