unintuative. Couldnt make workflow variables inputs

Until I used it in the workflow. This does makes sense but typically I would design the interface to my workflow and then implement bit by bit. I may only need the 3rd input param later on and Im still testing the first bits. But I cant pass this until later.
think of it this way. When you define an interface method you dont make them parameterless you generally know what you want to achieve. Perhaps a hint popup to let us know