One way of having some sort of dueling evaluation would be by adding some general statistics for dueling. How many duels had the person, how many did he win, how many did he loose? How many dp did he get/loose on average each fight (means, how strong were his opponents) ? I know that dp have been taken out because they were OOC and didn't tell much about the conditions of a player concerning dueling, but they could be re-added as one factor and together with the other statistics (total amount of duels and success-rate), form the base for the evaluation of a player. But instead of throwing out numbers, all these statistics could be reduced to one sentence, which could be added to the character evaluation.
Example: ABC had 1000 duels, won 750, lost 250 and got/lost 0.8 dp on average.
He had many duels, his successrate was 75%, and the dp he got/lost on average is quite high (considering that an equal opponent gives 1 dp). So the sentence could be something like:
ABC looks like an experienced combatant (<- states the total amount of duels), and his constitution implies that he did quite well (<- states the successrate), but still, the aura that surrounds him tells you, that there is no need to feel uncomfortable in his presence (<- states the strength of his opponents or in other words, how often he fought equal, weaker or stronger opponents).
To explain the three parts of the sentence above, another example: XYZ had 10 duels, won 2, lost 8, and got/lost 0.1 dp on average.
He didn't have many duels, his successrate isn't good. And he mostly tried opponents, much weaker than himself. The sentence for his evaluation could be something like:
XYZ looks like an unexperienced combatant, and the amount of scars on his face/hands/feet/whatever imply that he wasn't very successful, but still, the aura that surrounds him tells you, that you should be careful in his presence.
Whether or not you call evaluations OOC in the first place - and I know some players do - it could be one way to illustrate the dueling performance of players, including their general attitude towards dueling and their success. But anyway, it was just an idea, and when I saw there was a thread about the topic, I thought I'd share it with you in here, instead of opening a new one in the wishlist. Feel free to move it though.