If someone isn't RPing then that doesn't change. For someone who is RPing, they know what they should be RPing. They're acting out a failed diplomatic effort rather than a potentially successful one. They get to narrate how they fail.The idea that someone should "RP to the quality of the roll of the dice" I think is the wrong direction to take. Not everyone is an actor and not everyone is going to be able to RP a 19, even with group input. The player should be allowed to RP things in the way they want to the best of their abilities, and the game mechanics should be used to determine the NPCs reaction to that.
And the skilled diplomancer bard never commits a social faux pas or trips over their words. But their words DNA fail to sway someone.Most of the time you don't fail the attack because you bumbled. The enemy dodged or absorbed your blow. No difference here.
When the DM should ask for a Charisma (Persuasion) or Diplomacy check?
The method I've seen most often in play is that the player makes an argument and then the DM calls for a Persuasion check. Or Intimidation/ Bluff depending on how the interaction is presented.
Occasionally,the DM will modify the DC based on the results of the roleplaying that occurred before the check was made. Which is tricky as it adds two points of failure: you either do a bad job or roleplaying and the DC goes up, or the roll is bad. And occasionally you get the situation where they character says all the right things and does a beautiful speech but then rolls a "1".
The alternative tends to drop the roleplaying and acting and just has the character declare they're making the check and rolling.
It occurs to me that we're doing this backwards. That the second method is closer to the desirable course of play. We should roll the Charisma check first and then act out the actual discussion. We should find out the result of the check and then roleplay based on how well we rolled. If the player rolls terribly, they should modify what they were going to say based on that result. But in a good roll, they can really try and say something memorable, possibly with prompting by the rest of the table.
Or even the DM. Instead of the DM modifying the DC of the check, they should give cues and modify how the player is roleplaying at the table, suggesting taking points.
Thoughts?
Are the "roll and narrate" supporters saying that the DM should always call for roll? The outcome is always uncertain?
The players need to tell me their "Persuasion Approach" before any rolls. After all, the approach might be guaranteed to succeed/fail. Only when the result is uncertain, a persuasion roll is done. I guess here it can be reasonable to let the player first roll and then narrate.
What? No.
How did you get to that?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.