A character performing a persuasion check should attempt to describe and act out their persuasion.
Once complete, the GM should evaluate the description, and use that as a modifier to the persuasion roll.
A character that says "ummm, IDK, I guess I just try to influence them using my high charisma" should get no modifiers to the roll. A character who tries but entirely flubs the conversation should get a -1 (when appropriate), a great performance with an entertaining flourish to the description should get at least a couple ++ to the roll.
Yes, but if you don’t offer the same accommodations for the person who goes into excruciating detail about how they lift up an iron grate, there’s a bit of an unfair imbalance there. Same goes for someone who can’t necessarily verbalize an entire conversation on the subject, but can say, “I’d like to try and persuade the Governor that we’re perfectly capable individuals, and specifically bring up how we took care of the rats in the tavern cellar, as well as how we turned away the bandits attempting to burgle Mrs. Henderson’s store.”
If you don’t allow for either of those types of situations, you’re just promoting people who have a real-life charisma over those that don’t.
But you would do that. Someone that just says "I force the iron gate open with strength" gets no bonus, just a straight roll. Someone that says "I look for a weak spot in the gate and use a pry bar that I found earlier to force that spot open" maybe gets a +2 to their roll for extra thinking.
Also, it depends on the group, you don't need a one size fits all for this. If you have one or two people who are uncomfortable with going into detail, then you have to adjust your GMing to match the situation. But if there's just someone who needs a little encouragement, then you start throwing bonuses for extra roleplaying left and right.
The whole point is to make it fun for everyone (including the GM) so you're going to give bennies for out of the box thinking and extra effort, appropriately scaled to the group you are in.
Someone after my own heart. Say what you’re going to say and I’ll decide the DC. Just say “please” and probably get a straight check DC 12-14. Insult the guard’s mother and children will likely get a DC of at least 15 and maybe disadvantage. Going above and beyond probably doesn’t require a roll and nets you inspiration.
Do the same thing with combat. A barbarian that says "hit with axe" every round just gets a regular chance to hit. A barbarian that says "I charge in yelling my battle cry swinging my great axe while kicking over the chair between us as I advance" might get a +2 to attack that round (as long as they don't use the same thing every time.)
I have started doing that actually. I’ve moved over mainly to Call of Cthulhu, which has very fast and easy combat. I’ve had some great descriptions of combat manoeuvres that net a bonus die.
Dungeons: The Dragoning 40,000 is a d10 dice pool game with "stunt dice"
If you make any attempt at all to describe your action in-character (such as your example), you got +1 die
If your description was especially cool, or interacted with the environment in some way, you get +2 dice instead (I guess technically your example would likely be here, because a chair is part of the environment, probably)
And "crowning moments", the kind of really hype action that gets the whole table invested, the sort of thing that happens once or twice a session at most, earn +3 dice
It really helps keep people invested in the role play