I'm on board with DS on this one. I had been looking forward to the Sarevok NPC thing ever since I heard about it. From a power play point of view, he is a definate requirement in my opinion. But when it came down to his inclusion it just wasn't right. I've roleplayed one character consistently all the way through BGI, TOTSC, BGII, and now BGII TOB and it just goes against the grain.

"Sorry bro, no go. Take a hike back to the abyss. Oh, and don't let the door hit your ass on the way out!"

I too am slightly crippled by my roleplaying. I want to roleplay a really evil guy, but the advantages of high rep are sooo tempting, but "lawful good" just sticks in my throat, but...
Not to mention that the game is really made for do-gooders.
At least I don´t have any problem with Sarevok. But really, I consider both him and Viconia "one-size-fits-all" because you can change their alignment or not as you choose.