Right. All of which have to replace telling what you want your character to say with a series of social combat rolls. But you can't have both. Because if the object is to remove the possibility of the people "not comfortable with talking" from having to say anything and instead have the verbal jousting be about the dice rolls to determine whose "argument" was better... then you can't have any rules wherein the DM gives bonuses to what the players actually say. Because that's not fair, is it? So it's either one or the other... either players say what it is they want to say, or the entire social conversation becomes a dice-rolling game like combat currently is.Again, I am advocating for a social combat system that is intended to be used in social situations analogous to combat encounters: things like trials, dealing with courtly intrigue, and convincing powerful factions or individuals to do what you want. There are a number of ways to design the specifics, but in general it means giving players "tactical" choices and including victory conditions -- just like combat.
Now that being said... I'm not against the idea of someone designing said system. Social Combat systems have gotten made for all manner of games for years. So if someone does, and some people want to use it to remove vocal conversation as a determining factor in what characters in the game say... that's cool. I just don't think WotC is going to do it themselves though, as I believe they see things as I do. (General) You telling the DM what you want to do or what you want to say is the main thrust of the roleplaying game and why D&D isn't entirely a board game.