Played the HELL out of it on ps2, and going well through the Wii version. I honestly like the Wii version better. The controls do take some getting used to, but that might be a couple of things for me.
1) I have a small room. Therefore my actions have to be that much more precise.
2) I played the ps2 version. Timing is much more a factor, and I almost never think to dodge with the Wii version, (moving the nunchuck in the direction you want to dodge), just because I'm so involved with the rest of the game, and especially if I need to draw during the fight.
However, I will tell you, actually "drawing" the moves, is sooo much more fun. And once you get past the little nuances of the game's controls, it's generally pretty easy. Another half a foot back for me would make drawing straight lines much easier. I'll be the first to admit, I get better battle rankings, take less damage, and go through the game easier on the ps2, but it doesn't really matter, and the Wii just makes it that much more fun that I don't even care.
It's not hard to get absorbed into Okami. With the Wii controls, it makes it that much easier and more fun. Although with the rosaries, your arm does get kinda tired =P
Also, I'm about 18 hours through this playthrough, and it seems to be a straight port.