Screen space is always a problem for the clip layers. Sometimes a huge amount of space is wasted by a layer that doesn't change (eg a mask layer, colour filter or similar), changes infrequently, or changes in a way that you don't need to be able to see it. I use a bunch of layers for special effects, such as a track matte, where one layer typically only ever has one thing in it (a Layer Router source).
Sometimes also the "busy" layers are a long way apart; it would be great to get the things you actively want to see on the screen together as much as possible. Minimising layers or being able to resize any layer height woul be helpful.