I'm just going to start off by saying that it seems as though we're all thinking the same things regarding IDM, hip hop and jazz, but some of the ways we're saying it comes across as flawed. So that's just human nature.
Regarding improvisation, I would also second Solenoid's disagreement on improv, considering a very important element to my own music (which I call IDM). Also, I believe that ML's tiki lounge CD has an improv track on it as well. I've been very disappointed by IDM artists who tend to "play the album as it was recorded" (a very simple way of looking at it) in the same way I was disappointed by bands who just gave me the same shit they laid down on the CD. But this is so opinion-based that it's hardly going to ever going to come to an agreement--I like improv, maybe others don't. Whatever, that's fine with me.
Speaking of rap and improv, I listened to a friend of mine freestyle over an IDM artist at a show recently. She asked if she could give it a shot & the two of them managed to do something pretty cool. She said later that it was a weird experience because of the strange shifts in rhythm patterns in his stuff (think your typical run of the mill glitch), but to me it sounded pretty good.
Anything's possible.
cheers,
Mark
hellothisisalex
www.hellothisisalex.com / records.hellothisisalex.com
mp3s at www.raw42.com/cgi-bin/featuredartist.pl?artist=213
mark@hellothisisalex