Just got this idea for a tool that can make a map out of a demo. Whenever a player is touching or using anything in the demo it gets into the new map. Just an example, you play freestyle and want your tricks in a run. That tool would pretty easily create a unique map for your demo. Would you like to program that tool?
That's a good idea. However it's not as easy as one might think at first. You don't really see when a player or rocket hits a wall. You just see when the player velocity suddenly is blocked. Rockets explode on impact but also after time. However this is going to work out. Manual cleanup will be unavoidable.
Map design can be improved quite a bit, think THPS level builder with q3 complexity, combined with a run tool for live testing, plus multiplayer support for several designers and testers at once.