Ian Kognitow wrote:And since vampires are a rather run of the mill monster when one is protected from level drain, one decent fighter with that amulet is typically more than enough to dispatch the vampire lairs en masse...
Perhaps the most disappointing aspect of the game, particularly given their role in the main storyline, was the general weakness of the vampires...
I respectfully disagree with your assumptions and your conclusions. First of all, a minor point: a Fighter (or a Thief or a Fighter/Thief) cannot wear the Amulet of Power, so you need something else to protect them against level drain, such as spells that last only a few rounds. Or you might even send in your characters without any sort of protection and take your chances. (That's what I did when I sent in a Kensai/Thief with Boots of Speed and Potions of Invisibility to slaughter them--he was successful, but he wasn't completely unscathed.)
Second of all, the designers intended for you to follow a path that provides suitable challenges as long as you follow their suggestions (which are strongly hinted at). For example, the vampires are NOT easy to defeat if you start Chapter Three as soon as you have raised 15,000 gold pieces instead of waiting until you have completed all of the sidequests available in Chapter Two. If you don't play the game the way the designers intended, then it doesn't do much good to complain about a lack of balance.

Have you tried to beat the vampires with a 10th Level party on Core Rules or higher without using cheese tactics (like equipping all of your party members with Scrolls of Protection Against Undead)? I don't think it's easy at all for a first time player. Have you fought the vampires on the streets of Athkatla at night while observing the prohibition against magic (or suffering the wrath of the Cowled Wizards while you're already occupied with vampires)? Personally, I think the vampires are deadly enough under those conditions to be considered formidible. If you can't play the game without meta-gaming or using cheese tactics and you're disappointed, there's not much the designers can do about it. On the other hand, you can raise the difficulty level or install a mod like Tactics, but I don't think those are suitable for inexperienced players.
When it comes to evaluating game balance, I think the primary consideration is what an encounter is like for a first time player. What's it's like for someone who has played the game over and over is important, but it's only secondary. If you do a bunch of meta-gaming or use a lot of powergaming tactics or cheese, then hardly anything in Shadows of Amn is challenging, especially if you complete Watcher's Keep before Chapter Three. Encounters like the Twisted Rune are still a lot of fun, but it's very easy for a first time player to miss that encounter, and that in itself helps to maintain the balance. If you use a walkthrough (which the designers probably expected but didn't "intend"), that changes the balance. To a first time player who doesn't cheat or use walkthroughs, almost every encounter causes a lot of fear and apprehension. That's my experience, anyway.