Dance music can actually be pretty hard to write.. Of course there are those out there who just cheat and use prerecorded and sampled material, but really digging into a dance composition is intense.. Just programing the drum tracks from scratch can be some work. Whether the melody is boring really depends on the writer. A good dance song has smooth melody lines... A lot of hardcore programers program thier own arppegios and so forth.. I don't think it's like rap.. Rap is just a beat that's looped over and over with minor variations. Dance music can be quite complex. It has a better sense of movement within the score as compared to rap. Plus most of todays rap is just rip offs of yesterdays artists anyways... As far as Disco is concerned to me that's just vintage Dance and Techno before the digital age...

Squeak