What I wonder is what kind of sales they would expect from a game like House of the Dead Overkill on another system. It's an arcade light-gun shooter, meaning there already isn't a big market for it to begin with. But Wii is the best system for that type of game because it can already be a light gun without the need of a peripheral, so if Sega wanted to produce another game in that series then it would probably be unwise to release it on another system.
As much as people try to contend it, it would seem to me that The Conduit is a good indicator of what sells on Wii. It may be a new IP but it received generally favourable review scores, regardless of the actual quality of the title. New IP's can seemingly sell well on other platforms; recent million + sellers I can think of are Borderlands, Battlefield Bad Company, Left 4 Dead, Batman Arkham Asylum, Prototype, Army of Two, InFamous, Dead Space, Bioshock, Assassin's Creed, and Gears of War. Looking at a list like that, and the sales figures for "mature" games on Wii, it would seem to me that the majority of people with a Wii have already moved on to another system to satisfy their wants for that kind of game.
People also claim that games like No More Heroes and MadWorld are niche games. Once again, these are "mature" games which received favourable reviews, something which seems to sell on PS360. So what makes them niche? The fact that they're not shooters? Neither are Fallout 3, Assassin's Creed, Mirror's Edge, etc. They're niche because the market for "mature" games on the Wii is minuscule.
I know there are "mature" games like Call of Duty and Resident Evil which sell more than a million. I think that just goes to show that only "mature" games (and third-party games in general) which are a part of an established franchise have any real chance of selling on Wii. So it wouldn't be wise for any company to create an exclusive "mature" game for Wii as it'll post better numbers on the other systems, which means from here on out we'll likely see nothing but (possibly late) ports.
I think the only reason we try to refute these claims is because we want more games released for our favourite system.
It's amazing how a Nintendo game can sell 8 million worldwide and be considered a mediocre performance.
It isn't that it is a Nintendo game, but rather that it is a Mario game. If you go by percentages then Super Mario Galaxy is a slight under-performer based on the previous two 3D games. Super Mario 64 sold about 11 million worldwide, which is approximately 1/3rd of the system's userbase. Super Mario Sunshine sold 5.5 million worldwide which was 1/4th of the system's userbase. Super Mario Galaxy's 8 million isn't even 1/5th of the system's userbase. This goes to show
something, though I'm not sure as to what.