I was thinking today - a really useful feature would be the ability to add notes to objects.
I'm always revised models but keeping old ones around when developing designs for printing. But it's often really confusing knowing which one is which. Unless you make new projects each time and give them names there's no easy way of telling designs apart, aside from colour-coding them.
An icon you'd click to make optional notes appear or disappear would be fantastic. You'd then simply attach a note to each item when in note-viewing mode.