I like the range and speed challenge of the gigantic map. I run loose clusters, abundant habitable planets, abundant number of planets, and uncommon stars. Those settings maximize that challenge while keeping habitable planet numbers around 100-150. I enjoy it, although you are right, there's a lot of waiting when your best ships have move numbers pushing 70.
It's the number of habitable planets in the universe that loads the CPU. You can max out your processor on a large map if you run everything on abundant. Doing that with a gigantic map would really choke the CPU. Of course, you wouldn't want to play a game like that. Even if your system could handle the load, it would be more difficult than fun to manage that many resources.
If an "insane" map size was in the game, I'd play it. Just have to go from uncommon to rare stars.