Agreed though I think its very hard to quantify smite evil dps since it's so incredibly variable.
Personally, I think the mai nargument for Khopesh is not having to spend 12 action points, which is a ton on any paladin .. I can never take all the enhancement lines i want on my paladins. My new one won't even be taking pally cha 3/human greater adapt for a cha bracket, there's too much important stuff to take.