Nifft
Penguin Herder
The other social conflict system that I use regularly is Exalted 2e's "Social Combat" rules. They're just as intrusive as a Skill Challenge.As for KD's et al issues with SCs there are 2 things to note. First exactly how would you create an SC mechanic that magically meshes better with the flow of the game? We're all waiting to hear. ANY mechanical system is going to be something that starts and ends at some point. Its going to have exactly the same issues regardless of how you structure the mechanics. No amount of tweaking with the rules is going to hand to the DM a way to magically have it just work all the time.
I frequently use their metrics (Dodge/Parry MDV, etc.) even when the PCs and NPCs are being polite, and not trying to talk over each other -- if they try to talk over each other, or otherwise become less than polite, it's time to roll Join Debate & and use the formal Social Combat system.
So yeah -- even the best social conflict resolution system I've seen in regular play has this same intrusiveness issue. It would be sweet if there were a system that didn't, but I don't expect such a thing actually exists yet.
Cheers, -- N