A timed automatic save feature. You can use it or not. Sure it's a pain to be in the middle of something and have the auto save kick in but it's saved my bacon plenty of times in AutoCAD! Sure, I could hit the save button myself but when you get in the zone... well, you know. As far as the undo, allow multiple undos. Occasionally I'll try something and keep going with it only to change my mind and only being able to go back one step gets kind of irritating. Yeah, yeah, I know "save" again, but I may want to go even further back than that.