I think the, somewhat sad, reality is, is that Wii owners who care about fragging people online already have a PS3/360/PC for that and would sooner buy CoDWaW for those systems for A) Better graphics and B) Way better online (more people, more content).
Someone would have to be a Wii only owner or Wii and low end/laptop PC owner so that Wii is the only option for thier CoD thrills to purchase the game. FPS fans love their graphics and frankly the Wii CoD while the online experience is lag free and lots of fun it's also very limited compared to even what 6 year old FPS games offer.
I think Conduit will sell better as it's Wii exclusive and IF it's good then people will buy it for their Wii. I think everyone would like at least one great FPS for Wii. Conduit will fill that market as it's the only Wii exclusive FPS and offers great visuals and 16 player online, lots of modes (according to claims) with WiiSpeak support. It's the one to get, not CoDWaW which is better elsewhere. (although Red Steel 2 could prove to be a better offering than Conduit)
Good post. I'd add one reason why you'd get the Wii version over the others, though, and that's controls. Still, lots of folks prefer graphics to controls, so you're on target.
Does that work out to be a double-negative, or was that just crappy editing? You decide!