I think a simple reduction of 1-2 turns is needed, since at the current moment, I'm doing the battle with Archos, and one frost spriggat froze Rebecca(who's the only one who can undo Frozen) and Lakshmi and they remained frozen for 5 turns. Now while I get Ice element's ability is to freeze, it's a little overpowered at the moment, I find.
One attack should not be able to incapacitate 1 (or more) units for essentially the length of a whole battle with a group of enemies, or longer.
Edit: I suppose the same should be said for most other status effects, both good and bad. For example, I used Frost Armour on Harriet and with her iron helm, chain chest, and natural resistance + Hardened, she had 80% pierce resist and 100% slash resist for about 5 turns as well, which now is overpowered against the AI. In this case the AI simply never attacked Harriet because they they couldn't even inflict damage to her. In the heat of battle, having any status effect last for 4 or 5 turns seems just a bit too much imo.