A lot of people say they want the game to focus more on Social interaction and roleplaying. Or decries that there aren't Social mechanics. But what would that even look like?
Would we have "Social monsters" with a "Social CR" and care taken to ensure they have level-appropriate Social abilities? Would you earn xp for "defeating" a social encounter? How does one define victory?
The game as it stands now, it mostly comes down to "wily merchant has thing you want but charges too much." "I roll Persuasion, and get a 17." "DM thinks, decides that's a good enough number, merchant drops the price". You can add some nuance by allowing players to make other checks to get information that might give them advantage, but players have lots of tools to give them advantage as needed, or expertise to gain stratospheric check results.
And what's a social ability? What would it look like? Advantage on certain checks? The ability to auto win a social roll? Or in the case of an NPC, impose disadvantage or just ignore the results of a check, like some kind of "Legendary social resistance?".
Is it worth it to have a detailed system where all parties roll Social initiative, both sides have "resolve" (social hit points), and everyone takes turns trying to wear the other party down? Should there be a Social AC or Social saves?
And would it even be worth it, when players can possibly use spells to circumvent the whole system (as they generally do with exploration)?
I don't think the goal is to ape combat. If I zoom out a bit and think about Interaction in general as a mode of play, it's distinct from Combat, just like Exploration is. When I'm in Interaction mode, the stakes aren't life-and-death, but typically more related to my character's personality traits and their relationships to others. "Victory" in Interaction mode is my character being the lil' weirdo they are and making friends and allies and winning over enemies. "Failure" means isolation, violence, and dislike.
So thinking specifically about a "social challenge" in D&D, the challenge is usually to forge an alliance
of some sort. Think: Convincing the guards to let us in the city, infiltrating an enemy camp, asking the dragon politely to not devour us, etc.
That can be as simple as casting charm person
on an NPC, just like combat can be as simple as making a single attack roll against a commoner. If you want something that can't be solved with a spell, you need to raise the stakes - it's not just about charming the nearest guard, it's about getting an audience with an influential lord, or it's about not making enemies of all of dwarfkind, or it's about stopping the war with the orcs before it tears the land apart. Something that is bigger and more powerful.
And there you run up to the point that, as designed, social challenges in D&D are kind of supplemental to the core town-dungeon-climax loop. It hasn't got the mechanical weight that, say, a fight against a dragon has. You can get pretty big and layered with your skill challenges, but combat's gonna be bigger and more layered, just by the nature of the abilities PC's have and the weight of the rules attention if nothing else. If you want to play a game
, free-form only takes you so far.
So, say we want to change that and make social challenges a key part of our game. What this means is that forging alliances
become a big part of our game - and now we're playing something with more war and politics and intrigue, where if the heroes don't intervene, everyone falls to fighting each other and the forces of evil can take over (or whatever stakes make sense).
And then we're talking about things that other games do better than D&D. Maybe Audiences from the One Ring, or a reputation system, or a way to build a web of romance and relationships. And, definitely, you want PC's to be able to spend their resources (spell slots, actions) and exhibit certain roles (the diplomat, the pundit, the noble, the monster-speaker, the enchanter, etc.). And at this point you're definitely entering "why not just use another game that fits the vibe better?" territory. You could probably find a way to add this into D&D, but D&D is primarily a game about heroic adventure stories these days. Kludging a crunchy interaction system into it is sitll going to leave your rogue bored that they can't roll all their Sneak Attack dice and your sorcerer anxious to magic missile
So you can go harder than D&D does right now for social challenges, but I'd probably caution against going too crunchy on it, 'cuz the game ain't really built out for it. Though this is making me want to take those Creative Commons rules and tweak them to be a game more about forging alliances and earning peace than exploring dungeons and fighting dragons...