The game has a lot of replayability and I find myself coming back to it more often then I thought I would. However, of all the classes and stats, I find the Rogue and Stealth skills in general very underpowered. I've beaten the game with all other classes (Archer and Storm Mage in under 45 minutes), but I can't even get close with the Rogue class unless I find another Class book early on in the run. The fact that Rogues have less skills also seem unnecessary. My advice:
-boost the effectiveness of the Stealth skill: even with over 10 points allocated I was still being hunted by hordes after attacking one enemy
-allow Stealth to affect Ranged damage by 10% instead of Melee by 5%: chances are you will only get one hit before all nearby enemies become aware of you. Gotta make it count. And Rogues need to stay AWAY from enemies especially seeing as later hordes are bulky enough to shrug off everything but the beefiest attacks in the game.
-new Rogue skills - Blink (active) and Speed Up (passive): Going into the next floor surrounded by enemies pretty much means a dead Rogue even with max Stealth and good skill usage. Rogues already have 2 less skills than other classes, so let's fix that. Blink let's them get out of danger. Speed Up just lets them cover more ground than other classes since covering space (either in retreat or a sneak kill) is necessary.
-buff Sleeping Dart: I can't even count the number of times my target would wake up immediately from one. Deep sleep? Pfft.
Anyways, overall good game and hope to see a sequel.