Saint's Row or 2 isn't a graphics powerhouse but it is better than anything the last generation could do and no I don't think the Wii could handle it as it is either. I love Nintendo but I have to be realistic here.
Look at Dead Rising, it didn't exactly push the limits of the 360 and while it might turn out to be a great and fun game on the Wii, it won't match the visuals of the 360 version. The same would be true of a Wii version of Saint's Row. It could be fun to play and could look decent as well but it won't look like it's HD versions.
I'll come up with something better eventually...







