The thing is that it has become four times or so more clicks. It used to be that if you hit 'backspace' or 'delete' it just tore up the last node you put down. That way you could quickly undo as many segments as you wanted. Now you first need to end the routing operation, delete the segments you want to undo, which kicks you out of routing mode altogether, enter routing mode again, and find the end of the track you were laying again to start routing again.