While googling for exact information what the difficulty level settings change in Icewind Dale, I came by several complaints of IWD being too hard, like this: http://werwolfesden.blogspot.fi/2013/03/icewind-dale-and-difficulty-settings.html
I don't know, I am not finding the game that hard, at least not yet. I think I had more problems in both Baldur's Gate 1 and 2, in the early game. Especially the semi-bosses have been push-overs so far in IWD, like that Lizard King or something.
Playing IWD on normal difficulty, but:
- "get max hitpoints on level up" is enabled; I dislike the idea of leveling up being partly based on luck, even if rest of the game is.
- I used quite a lot of time and rerolls during character creation, to get something like 85-89 ability points to all my characters. And generally also trying to find out a great party with correct classes and races.
Those probably affect it too.