Legendary Nintendo designer Shigeru Miyamoto recently spoke to ONM on Wii Music and bridging the hardcore/casual gap.
The official magazine quizzed the Mario creator on the game's initial lack of traditional appeal, and how by digging deeper one might find something to enjoy. He feels that with the casual crowd starting to play with the core folk that it'll eventually bring these different types of games together.
...There are many hardcore gamers playing with casual gamers and I believe casual gamers do get into hardcore games too. I think one of Nintendo's missions is to destroy the barrier between the two and I believe Wii Music contributes to that.If casual gamers are defined as people who spend less time playing a game, as opposed to those who play a lot and like to spend a lot of time exploring every detail of a game, I think Wii Music means something to both groups.
One of the most disappointing aspects of Wii Music for most was the song selection - a huge emphasis on classical, public-domain tunes, some less successful commercial hits and a measly 5/6 gaming melodies.
Koji Kondo is responsible for the music in many Nintendo games and he selected the songs. The criteria he went by was that they must be well known to everyone and they must be simple. When the chord progression is simple, the song is better suited to the ad-libbing you do in the game's jam sessions. Of course, if we only included simple, traditional songs, that might be boring for some people, so that's why we included some contemporary tunes as well.