"Being developed seperately"
I've been a PC Gamer since the Commodore days, haven't owned all that many consoles. I did however break down and buy a Wii, because the PC doesn't help much when you have several people at your home crowding your living room. So I bought a Wii, and quickly became dissapointed with the quality of games, as most seem to be bargain bin trash. Seems like most cross platform games that get great reviews for PC, XBox 360, and PS3, get horrendous reviews for their Wii versions. The Wii so far feels like the system that most developers don't quite know what to do with. Then it is taken a step further when many games, such as the Madden football games, which can only be played with the Wiimote and Chuk...which is more awkward than anything. There are a handful of games worth owning, such as Brawl and Kart for example, but all in all...the Wii has been extremely dissapointing.
That being said, I'll definitely buy CoD 5 for the PC, but the Wii version isn't something I'd hold my breathe for.