"I'm trying to explain that what could be a great game on one system, may not be on another."
"the wii can't support these types of games"
Games that are large scale just means they won't look as good. Since the Wii is more powerful than the system that San Andreas was made for, it obviously can do large scale streaming areas. The details won't all be there, but good level design is not something that magically can't be transferred.
"but it's not like you can take a game like uncharted2 or halo or anything similar, and convey the same experience"
Halo? The graphics won't be as detailed, but come on!
And I know these are first party games, so they won't be done anyway, but you are really getting it wrong here. Unless there is something integral to how the game works that needs the multi-core processors (and of the few of those, one was ironically one of the few actually converted to the Wii), the game will simply have the graphics and some background details reduced compared to the HD versions. See Modern Warfare (not including local multiplayer was a choice (not the best one though), as the online multiplayer works).
A flashy-first game is awesome when it comes out. A great-first game is awesome forever.
Plus, just for the hell of it: Kelly Brook at the 2008 BAFTAs