As a Wii owner since launch, i look at the reviews that play the Wii controls negativly with a grain of salt. Anyone with the slightest experience with a Wiimote should have NO problems with the celestial brush in the game.
I for one love the controls, and instances of my brush inputs not being recognized were very few and far between.
Needless to say, i would strongly recommend Okami.
F@ck Ubisoft and their commitment to Wii shovelware.