The problem with the wii games is that they generally cannot hold as much data/ cannot run the same level of graphics and gameplay depth that the others can. (When I say gameplay depth, I mean, simultaneous gameplay, like an RTS computing thousands of different things in real time, not how good the gameplay is)
Therefore, when making a wii game, the gameplay has to be that much better, and use less tools with which to run it. Fewer environments, smaller levels, lighter graphics+details. The dev has to be much more clever to make it seem like the player is getting the same thing. For instance in SMG, the planets are all relatively small and everything is on a timer or patterned. This means that the system only has to render a small part of the environment at any one time, and even cleverly hide a loading period when shooting to other planets.
It's the same with all the wii games, and DS games for that matter. It's hides in "style" or "scope" or "rails".
Additionally, most of the core audience enjoys games with lots of replayability and addictiveness. Minigames and challenges to improve scores are littered among the wii titles.
Now, taking into account the increased cleverness needed, and increased gameplay replayability, you're looking at a couple things. (Note that "-" signs do not mean bad, they mean standard)
+replayability +cleverness (pretty much only nintendo)
+replayability -cleverness Minigames
-replayability +cleverness ex: Madworld, the Conduit
-replayabliity - cleverness (this one entails a normal core ps360/PC game)* impossible due to system constraints.
Note about the above: I'm not saying anything above is fact. I'm trying to describe how different it is for successful games on the wii. In order to make comparable games, you need to tone down the scope and inject addictive qualities. The simplest addictive quality is score, the second, is collecting. However, the kind of games that are popular on pc/ps360, don't involve score for the most part, and the ones that use collecting, use it in such a fashion that it would not be possible on the wii. There are just too many varied things to collect/unlock. Additionally, when you want to improve on one of these things, something else has to take a hit. And that's where the cleverness comes in, and why cleverness is the most crucial aspect of this whole thing.
It costs a lot of money to make a clever game. And that is why you don't see many of them.
Essay Pro