Punkoinyc: Well I don't know about the original release, but in the English language version the dialogues were poorly translated and absurdly long and convoluted. It needed serious editing.
A lot of the time the game also didn't clarify what the player was supposed to do. It's nearly impossible to play the damn thing without constantly consulting the internet. I remember one quest with a Bishop in a crypt and you had to destroy some sort of item to hurt him, but it was never made clear in the game. I had to google it, and that happened a lot.
I don't comprehend Czech, so I played the English version too and think the dialogues were rather good. I know that most people today don't like to read anymore, but for me it actually was fitting and it's one of the reason why I compared it to Fallout: A lot reading, in addition to the grim setting, depressing athmosphere, harsh characters, etc...
You get hints for a lot of stuff if you talk to everyone the right way, the amount of information you get depends and how you handle dialogues and situations though and how careful you listen to people.
I had to use a walkthrough too a few times, but only for dungeons and way less often than for any point'n'click adventure.
What this game needs is time and patience and that's why some people say, that it's actually too much oldschool and I can't blame them although it's also a selling point and makes it special.
Punkoinyc: As you mentioned, the character classes were horrendously unbalanced and needed work. You downplayed how badly unbalanced the paladin really is. He's useless, the developers should've just cut him before putting out the game.
It may be hard to believe, but I've only finished the game with the Paladin yet, still have to try the other characters but believe those to be much easier.
I had to use some scrolls for spells sometimes though, so if you try to play 100% melee it may be impossible indeed.
I remember one mean game-breaking bug that badly needs fixing though. There is one enemy that drains your life endlessly after he hits you, even long after he is dead and you are back in town already and got healed. I can't remember anymore what I did to get past him, but it's in one of the threads on GoG's Inquisitor subforum.
I wish, the devs wouldn't have abandoned the game and polished it a bit more, but in the end it had a similar fate than many RPGs I love - thinking of "Vampire - The Masquerade: Bloodlines" too here... with the difference, that there are not even community patches - not even one.