Not critically important, but irritating is how when printing multiple colors by object, the software often changes from color to color repeatedly - either the printer should, to prevent excessive purging between colors, print the same colors all one after the other, or allow each color group to be printed by-layer all at the same time. I suppose it’s possible to emulate this by making multiple parts part of the same object, but I haven’t tried that, and it seems kludgy to do so.
Adding this sort of functionality to the slicer would be extremely helpful, and minimize material waste.