Melt ice would be more useful if the enemy stands on it.
Sorry forgot, you could freeze it while he is swimming and walk over and hit his head with something hard.
Well, one use of freezing water would be to walk over it without needing to swim. But unless Bethesda took out the water walking spell, that's really not so useful.
It would still be nice to see something like this, though, we've heard about being able to set the environment on fire in Skyrim, so I'm hoping other spells get environmental effects like that as well, we'll see about it, I suppose.
I personally would think that it would be cool but on a different note water freezing in skyrim is something I would like to see
I think we can safely assume we'll see static ice sheets over some of the water in Skyrim, I mean, Bloodmoon had that too, it's really not that hard. Just create an ice sheet model, and place it above the water in some areas. Now if you could actually have ice dynamically freeze on water, that would be more impressive.