However like Nard, I can't think of a single counter-example (with the exception of the aforementioned Music games like DDR and GH) where music is more important than design, code, and art.
Not more important but as much as important as design: REZ
Check this game out, play it, experience it, feel it. It lives from style, from music without being a classic bemani game like DDR, Samba de Amigo, ...
About your other complaints: No I'm not going to open another thread. I've now said everything I wanted to say about this topic as the inital post sounded a bit like "music is not really important anyway" which is wrong (imho). No offense meant and no offense taken.