Corwin of Amber
First Post
You're assuming vengeance as a motivation. Equally as common is the old "fight fire with fire" trope where a hero uses evil methods/powers/etc. to fight evil. Just as a Malconvoker can summon fiends to kill fiends, a good ur-priest could vow to only steal power from evil gods and use it to fight evil.
I guess it seems that that is an unlikely situation, given things like the fact that the Paladin cannot allow any unjust act -even in the interest of good- happen in his presence without potentially needing to attone.
I think it boils down to this: Would you allow a Good character in your campaign raze a village of innocent people belonging to an Evil nation bacause they did the same to that character's nation? That seems to be using an evil method for a good cause, shutting down trade and economies of an Evil nation seems like a good thing to do, but the sacrifice of those people does not seem good (although one might argue that it may be Lawful).
To be honest, I don't think it would meet resistance if someone wanted to house-rule it to be neutral. There cannot be a version of each class for each situation in all of the books. It is akin to the suggestion that you can alter various classes that are dedicated to a single god by shifting to to annother god and changing a few features. It would be like expecting them to make the Shining Blade of Heironeous class reprinted once for each possible god in the complete divine, rather than a note on adaptations.
Plus, this game was meant to engender creativity and ingenuity. I would venture a guess that the rules were meant to be rather fluid; they are less like rules and mroe like suggestions.