heres the deal with the graphics, the biggest problem with doing ports on wii is that it apparently lacks shaders like the new systems(and xbox), however here are a few statements to think about.
Wii is more powerful than GAMECUBE
Xbox had some gorgeous games thanks to two things shaders, and textures
the truth is gamecube could actually process twice as many textures as xbox, but gamecube had less memory than xbox, also due to limited disk space less textures could be stored on one disk
Wii has more memory than gamecube and bigger diskshttp://www.wiisworld.com/wii-specs.html
here are some unofficial specs, but they seem about right
having lower graphics usually doesnt stem from having too little processing power(the truth is systems usually have more processing power than it can output), but a lack of ram
Wii games should have
Crazy detailed textures,
with bigger disks, and more memory they should look great
low end shading,
because the shading is not so great, it would be possible to use its crazy texture power to fake better shading
and they should actually balance out on polygons because while the processing power isnt as much, its always at a lower resolution...which leads to jaggies though, however that can be fixed with anti-aliasing, unfortuanatley thats processor intensive, but smart use of polygons can balance it out.