This comes from a place of frustrating when constantly having to use all of my favor rolling prophesies but, I think it would be pretty sweet if there was a central telescope that was for global lenses. This way, your global lenses would actually apply globally, instead of having to put them in every telescope, and you might actually use the lenses for local telescopes. It would also help prevent people from rolling 20k favor looking for a prophesy they want to do.
As an aside, just remove the prophesies for campaign and arena of champions. Nobody wants to do those… all they do is lower the chances of you getting a prophesy you actually want.