the1st_fret: The irony of your statement is that a lot of hardcore gamers feel the opposite way: There aren't enough complicated, hardcore games on the system...I think all of this is a case of launch-system blues...there aren't a lot of games to choose from in general at this point.
Twighlight Princess really isn't a good example of Wii games anyway, since it was designed as a GameCube game and then reimagined as a Wii game. The next Zelda will probably be more in line with the idea of simplifying hardcore games...but at the same time, "simplifying hardcore games" may be a paradox. When a company wants to make a 50-hour game that never gets "old", it has to build more and more complexity in, to the point where it's not really possible for that game to be easy to play. Imagine 50 hours of Wii Sports matches.
Which brings us to the original point: the huge hardcore games are getting too long for some of us. Others accuse us of being pansies or whatever, and you know what? Maybe we need different games for different people.