I wish the extrude selection option was more obvious. I realized one of the reasons I missed it in the past is that it doesn’t show up until you start extruding. I haven’t looked, but a keyboard shortcut would be helpful here. I think the best, actually, would be to have the option be next to the number entry after you click on the extrude arrow. (See below screenshot).
Having the ability to input in a different unit or do calculations is still high on my wishlist.
It’s certainly something we should improve. One of our teams is actively working on revisiting these kind of things (= smaller and bigger annoyances in the basic interactions) and improving them.