Let me explain for those not familiar with this game:
1) You cast the spell but instead of being able to roam freely you just stay a bunch of feet over the last ground you have touched. Yep you cannot rise.
2) You cannot use it to fly down from a very steep mountain as it consume a lot of magicka, last maybe 15 seconds max, and (i think) if the ground is too far away it doesn't work.
3) In a dungeon however is quite a beatiful spell as it allows you to go to an high enough reachable place and from there, casting the spell, reach the hidden spot full of treasure we all like to have in our game.
4) In the outside is still usefull as it allows to go from a cliff to another (they have to be near though)...in this case its final effect is more or less as sueful as a standard bridge.
Since you are never very far from the ground the AI should not be upgraded in anyway way and also the draing distance could remain the same.
So what do you think?
P.S.
I would still prefer the free form levitation btw...