Vocenoctum said:
I couldn't see the orcs appreciating the "mercy" of wiping out 90% of them and sending the rest back to whatever hellhole they crawled out of.
Frankly, what the orcs think about it is irrelevant. What's important is that the paladin does the right thing. What's tricky is that the right thing isn't clear.
In a case like this, incidentally, I would let the player make almost any call he wanted, without the threat of a loss of paladin abilities.
Either way the orcs will be a problem down the road too. If you're not redeeming them in any fashion, it's better to burn them to the God of Good.
This is probably one of those situations where the actual best long-term solution is precisely as you suggested: wipe the tribe out. Leaving them to starve in the wilderness isn't exactly a good thing to do, and will lead to the children growing up evil and causing problems. Taking them as slaves just stores up the problem too, as you'll one day face them revolting against you.
Machiavelli's "The Prince" addressed issues very similar to this, and his advice was that although it was unpalatable, in the long term the solution that provides the greatest good for the greatest number is to exercise a degree of moral flexibility, and do the horrible.
However, that is simply not an option for paladins - since in the RAW orcs are not inherently evil, the paladin simply
cannot murder defenseless orcish children just because he knows that they will cause problems at some future time.
As I mentioned though, we tend to avoid such moral quanderies in our games. You won't encounter orc warriors with a baggage train full of kids. I don't see how this scenario (orc kids) is in any way unique to Paladins though. A LG fighter should (in the same campaign) feel the same tug of concern, and the cleric of Ilmater would probably be horrified at leaving orc kids uncared for.
The problem is unique to paladins because for the other characters you mentioned it's a role-playing concern. For the paladin, it's a matter of losing his powers if he does the wrong thing.
My approach to it is rather different to yours: I am willing to place the PCs in the situation you described, because I am interested in tackling moral quandaries in-game. What I am not interested in doing is screwing over the players, even of paladins, so as I indicated above, I would essentially let the paladin make his decision without fear of loss of power.