el-remmen
Moderator Emeritus
A friend and I were discussing this yesterday and we liked the idea of each NPC having a few tags/traits that if the player could incorporate them, they get a bonus on whatever final roll is called for (without a full on social combat system, i tend toward one singular roll at the end of the roleplay conversation to judge how it ultimately went). Things like Greedy or proud or Loves Their Mom or whatever. You could also offend one of those traits and earn a penalty. We also discussed the idea of a Secret, that if you discover it and incorporate it, it gives you advantage. Like if the new king secretly killed his father, and the PCs could let him know they know without blowing up court, they could get advantage on the roll to persuade him to send troops to defend their home or whatever.
The last 3E game I ran used an Influence and Reputation system for influencing social rolls that we cribbed from the first A Song of Ice and Fire RPG - but the many modifiers and high rolls made that easier to tweak in increments than I think would be easy for 5E and I am all for easy.