Well, first this game doesn't offer my particular play style. No stealth, no sneak attacks, no back stabs or pocket picking. An rpg without a rogue, go figure.
Also, the concept of an RPG is that the outcome of any particular challenge should be based on the skills of the character, not the player. The assumption that ever player has the reflexes of a teenager is a grave one. I actually went back and tried a combat on all three difficulty levels. There was no difference in their outcome for the most part. Easy level was just as hard to beat as normal or hard. I found no difference between damage done to them or to me.
I can only assume that that is a flaw in the difficulty slider. The game is locked in the difficulty setting in which I started the game. I would have to adjust the setting to easy 1st I think (tho I haven't tested it yet) then start a new game. However, I really not willing to go through all that again when an upgrade is slated to be released.
There is a skill that lets you shoot enemies before they see you, and there is a short duration invis skill that lets you sneak up to/past enemies. You also bash the game for using similar elements that other RPGs have incorporated, and then complain there was no rogue class. That doesn't seem to make sense. Innovation or conformity- pick one to complain about. You can't dislike both.
It is quite easy to dodge most spells and ranged attacks, and to back away or strafe to avoid melee attacks. If you stand still and let everything connect, of course you're going to take a lot of damage. Use some strategy and it's fine, and definitely a welcome challenge.
I've noticed a large difference between the difficulty levels. I play on hard, have played through Broken Valley as a mage, archer, and melee fighter, and haven't had any issue of running out of potions. I also believe that adjusting the difficulty slider while you are playing does change the difficulty level, it's not locked into what it was when you made the game. I haven't tested that specifically, so I could be mistaken. One thing that I observed that suggests you are mistaken is damage from fire and poison. Standing in fire on easy difficulty takes forever to kill you and food generally outheals it. On normal or hard difficulty, slamming down potions still isn't enough to keep you alive.
You seem to be spending a lot of time complaining about a game that you said you hated. Why? Return it or give it to a friend and move on if it wasn't your cup of tea. It doesn't look like anyone is going to be able to say anything to change your opinion of the game. Personally, I love it and have enjoyed it more than Oblivion, Torchlight, Titan Quest, etc. Some of the story could be better, but what other RPGs for the PC have story lines that are 100% awesome? I can't think of any. Diablo 2 is still wildly popular 10+ years after its release, and I can tell you it's not because of it's story.