Do you mean collapsing maps/mats into one visual item which you can then expand? If so, then I admit that would be lovely. I find myself minimising complex mats to just the preview a lot, also using multiple tab views to keep things organised.
I am completely enamoured with it though, the ability to visually represent and edit the chain of maps/mats hugely outweighs any visual complexity and the archaic hopping up and down in the old medit for me.