Its not just that they arnt super-high-tech in terms of engines, its that the artwork just plan sucks anyway.
I've always said it comes down to the artwork rather than the tech. This is a good emample of a game that would have held it's own on the GC.
Techs nice obviously but not required to make a beautiful game. If artists could be bothered/had time/had money then they could layer every square inch with intricate homemade textures and labour over level design etc then they could make a beautiful game with the wii tech. Fur in starfox adventures/paint in super mario sunshine etc. GC hardware does not have to mean 64 graphics mixed with PC pseudo-games.
The problem is that they don't make 'em like that.