It is like maximus said. A lot of fight will be extremely easy depending on how you begin the fight. There is many way to do it but they aren't equal and some are merely impossible.
Try to win against the goblin camp with a warlock if you pick a fight without taking position. You will probably have a hard time whereas if you begin from the top of the fortress there will be no difficulties at all.
So if you want to be spontaneous the game will be way harder and in some case nearly impossible (especially if your character aren't a bit optimized).
In the end of course it depend of the player and maybe I missed some strategies to make the game easier but from my point of view the game could be very rude if you don't take advantage of his mechanics.
