Slowfall to me was both an entertaining spell to use and a very useful spell to use in Morrowind. It would slow down your descent when falling, and completely negate any fall damage you would otherwise receive while the spell is in effect. Unfortunately, this spell did not reappear in Oblivion.
Do you want Slowfall back?
With all the mountains and high elevation in Skyrim, I could definitely picture this spell being very useful to alteration masters.