It would be great to have the ability to reorder workflow steps with a simple drag&drop, there are often times where workflows change, new steps are added in and things need to be reordered.
It would also be quite handy to have the ability to duplicate workflow steps, there are sometimes cases where you need to do the same action but with a slight change (e.g. sending different emails to different people) and it would be quicker to just duplicate the whole action and change a couple things.