So far....
The inventory system is terrible. Whereas RE4's system made the game almost too easy by the middle/end of the game (I had so many healing items that I never had to worry about dying besides the few occasional instant kill sections), RE5's system contains a little too much micromanaging for my liking. This is directly related to....
Sheva's crappiness. Her AI is awful for the most part and you can't program her behavior. She's pretty liberal with healing items and is an ammo waster. I always have to give her ammo and she has this terrible habit of giving me ammo when I don't need it. It's especially lame that ammo sharing is all or nothing. If I have 35 bullets, I can't give Sheva 15 bullets (unless I just haven't figured that out yet). The game was obviously meant to be played co-op, but the best co-op games have good enough AI where the experience is a little less frustrating because it doesn't require so much babysitting.
The graphics are amazing though even the PS3 version doesn't output in 1080P (Booooo!!!).
I basically just focused on the negatives, but I don't mean to say that RE5 is a bad game. It's great. If not for having a partner (and the option for co-op), it's definitely what you'd expect out of a sequel to RE4, which is a good thing. Thus far, the voice acting kills RE4 and the plot isn't as fractured and ridiculous. I'm not sure why people would want this on the Wii as the best part about this game is playing online with voice chat and I don't know if this could be the same on the Wii with Wii Speak and crummy online structure. At the same time, RE4:WE is still a better playing game. I'm having a hard time adjusting to using the Dual Shock 3, mostly because it's not the Wii remote and nunchuck, but it's no Gamecube controller either.