Unfortunately, God is the Wii version does not so well as the older PS2 version.
Wiedermal makes the Wii controls that whole bit maggoty.
In most places, it gets it pretty well but then there are also places that are again playing absolutely grottig.
It's not unplayable by far but sometimes you need 3 attempts to master certain brush techniques. Especially intricate patterns like Inferno are a hit or miss, and are usually only triggered if you do not want it.
The Wiimote is simply too vague and shaky as that could really draw accurately.
Due to the control, there are also places where you get stuck in the Wii version WHILE it was on the PS2 no problem. That is a shame and it is annoying sometimes really something. Also in the fighting, it is sometimes a bit exhausting to always shake the Wiimote and the button assignment was in my opinion in the PS2 a bit better.
For technical aspect you have to say the following. The Wii version runs in 480p instead of the PS2 version in 480i. There is also a 16: 9 support so you'd think that you should have that best picture to a HD TV via YUV cable.
Well I can not agree so completely. The PS2 version looks on the Playstation 3 play much sharper and clearer than on the Wii.
Either it is up to the HDMI transmission or on the perfect emulation of the PS3. Only nerves the edges and the colors are on the Wii much stronger.
Since the control is better than on the Wii I would recommend to anyone (the choice has) to opt rather for the PS2 version.
CONCLUSION: Okami is a great game and absolutely everyone should have this game gambled times. It entertains immensely and has a playing time of approximately 50 hours. Whether PS2 or Wii is not so very important because it is well on both systems but still I would recommend the PS2 version.