I know, I know "Khopesh's have better base damage than scimitars/rapiers on enemies that can't be critted".
But here is an interesting conundrum:
TWF paladins can use Scimitars at Character Creation, whereas Khopesh require an extra feat. The thing is, paladins don't get any extra feats at all while leveling up (unlike fighters), and trying to build a pure TWF DPS paladin for the Capstone powers will have the weapon-related feats take up virtually all the feat slots except for one (which presumably must belong to Toughness if you want a character that doesn't die if a pit fiend so much as sneezes on you).
With the Improved Critical Slashing feat, a Khopesh has 20% chance to crit with a x3 multiplier. However, rapiers and scimitars would have a 30% chance to crit, which is huge if you're a twf. Against mobs that cannot suffer critical hits (and do note that their kind are relatively rare compared to most of the mobs you face in the game... with exception to the golems), it would make more sense to either use a two-handed weapon, or switch to longswords/battle-axes.
That being said, a burst weapon (especially an elemental burst weapon + Risia burst) is likely to do more damage in the long run when scimitars are used than when Khopesh's are used. This especially true if you have greater two weapon fighting which makes off-hand attacks 80% likely to occur.
So I ask, why do Paladins *NEED* to use/have Khopesh weapons (and lets' face it, I haven't been very impressed with most of the epic weapons out there; the best epic weapons appear to be the Two-handed weapons that paladins don't need to waste a feat for).