The obvious answer is that there is no way that The Conduit  can outsell KZ2. The Wii has never had a FPS smash hit and a lot of its user base is not likely to ever really support one. The PS3 does of course have a smaller install base, but it's a base that likes M rated FPS and they can be counted on to vigorously support the gradually eroding number of exclusive releases.

For the Conduit to outsell KZ2, either KZ2 would have to be a flop - unlikely, or something would have to light a fire under the Conduit and propel it past all other FPS efforts on the Wii - just possible. For it to happen, first the Conduit has to be a fantastic effort both in graphics and gameplay. Early video and screen capture indicate that High Voltage may really deliver a great product.

 Second, Sega has to really promote and publicize the game. Sega is making a real commitment to the Wii and understandably so. Up to now the Wii has unquestionably been the big money maker for Sega and logically the console they will commit more resources to. So I think their enthusiasm for the game is genuine and it would be obviously be in their interest to heavily promote The Conduit.

Even with a great game and a good solid promotional campaign, I think it would still be an uphill battle but there may be a wildcard in the deck and that is Motion Plus, and to a lesser extent Wii Speak. Is Motion Plus, vital to The Conduit; probably not. Most players think the Wiimote and Nunchuk alone, if executed as well as in Metroid are nearly perfect for FPS already. Besides, High Voltage has made a commitment to make the game great whether you have Motion Plus or not. Still, extra precision is a good thing, even though that's not what may make the game take off.

Does anyone doubt that Wii Sport Resort and Motion Plus will be a huge hit selling millions? And naturally all those millions will then want something else to use their brand new Motion Plus on and the highest profile, essentially a launch title, game around will be The Conduit. Even people that have never tried a FPS may want to get it just because it has Motion Plus and Wii Speak and with a base of, by then, 50 Million or more that might be enough to propel the game into the superhit category. So I think there is a chance that it could end up outselling KZ2.

Hell no!
An stablished franchise against a new IP? I don't think it's even have a chance.

And then why does it sell worse than the PS3 and 360 versions? THe PS3 and 360 market is flooded with great FPSs. The Wii hasn't had a good one since Metroid Prime 3.

I mean. If the Wii userbase only buys 600k while the 360 and PS3 base bought 4.5 and 2.6 milllion each. The Conduit doesn't even have the help of the holiday season. 

of course not. Plus, the bundles ;)

Conduit will outsell Kill Zone 2 due to Wii having 2 and a half times the install base of Kill Zone 2.

lol, im sure they will help

The simple fact that KZ2 will probably be bundled to hell and back makes it very likely to sell more... And even if it wasn't for that, I'd still say no.

The Conduit would have to be a massive hit to outsell KZ2... That's very unlikely to happen but I'm not going to say impossible either.

My point is that many multi-console owners chose the 360, PS3 or PC version over the Wii version.

Theoretically yes, simply because the Wii has more than twice the PS3's userbase.

Practically? Probably not. It's the first game of a new IP, and being published by SEGA, which... I dunno. If it doesn't have Sonic in it, SEGA games feel cursed. Maybe this will help turn things around, but I can't count on it.

However, I don't expect either game to meet the goals fans have for them.

The Conduit will be a success if it can hit 1m, but 2m or more would be a huge surprise.

Killzone 2 will hit 1m easily, and likely go multi-plat, but anyone expecting Halo type numbers are deluding themselves.

Wii Fit and Gears of War say "hello"!