Alot of hands-on articles with HD versions always say the framerate drops and I think they say it might have slow downs. Also that the Were-Hog sections control bad.
I havent read any Wii previews but from all the Wii footage thats been released lately it defintly keeps up with the HD versions in Visuals and it looks smoother IMO.
I made a thread about this same subject on SW:TFU and the Wii version did turn out to get a better reviews.....at least from IGN.
Check out the latest trailer for Wii below.