TwinBahamut
First Post
You know, this is exactly why I think there should be a more involved social combat system in D&D. If you leave things to be formless and rules-light, then diplomacy will primarily be handled by whichever player is most vocal and assertive. If you leave things down to a single number, like 3E's Diplomacy skill and Charisma stat, then things quickly devolve down to all diplomacy being handled by whoever has the highest relevant skill. Both systems tend to dump it all on a single player, whether that player likes it or not! In many campaigns I've run, the group often just let's one person handle it all, even if that player specifically tries to get other people involved, and does not have the highest Charisma stat.The biggest thing that seems to get people more confident in speaking is for everyone to be more involved. It is much easier to be involved in a group activity than it is to place yourself out there and take on the burden of roleplaying by yourself.
If you have a more structured and complex system, then you have far more tools to encourage everyone to get involved, and can provide benefits for teamwork the same way you can in other complex game systems like combat.