Party based would counter the competitive part of the game, but if chars are close to each other, the game should automatically take the guy with the best stats. Probably similar to leadership?
But Persuasion could be a bit problematic, specific stats have there more impact than the Persuasion skill itself. Honestly Persuasion feels kind of waste of point as well. This +1 per point just doesn't matter if there are stats with 20-30 points in the game.
