Should we then permit Neutral Good paladins in the game?
I'm probably joining in here because I sense difficulties in playing the game. If we fill the gaps of the current Virtue mod by judging every action of the game, a paladin will become close to unplayable if he still falls at Virtue -1 OR Lawfulness -1 (as proposed in the first post). BG2 is no PnP; its story and interaction opportunities don't offer the same freedom as PnP roleplaying between players and DM, and you have to take the limitations of choice into account.
Some of them is the impossibility to redeem once sins, regain favour with your godhead/the order, explain your actions to your superiors, await and accept their judgement, etc.
This is a computer game with a predefined story and predetermined reactions; without greatly expanding interaction, the judgement of actions won't be fair.
That includes the evil ways on the other edge of the spectrum - the lack of opportunities for evil players has often been lamented, and though they don't suffer the same technical penalties like paladins, they often don't have much choice than being good or leaving the quest be.