Compare and contrast:
I think the role the "Aristotle" (AKA Rachel Barney) describes is probably quite a useful one in the right context, the problem is that the nature of Trolling as defined in that paper is intrinsically that it is done not in the right context.
There's a thing that happens in Vernor Vinge's "A Deepness in the Sky" where the Evil Overlord ™ is experimenting with different configurations you can put a group mind in. I sometimes think about this as an analogy for how to construct better modes of group problem solving (in a non-evil-overlord way that in no way involves my using the army of crows that I don't have to impose my will on the unsuspecting masses. Yes) .
In particular, I think it's often actively useful for someone to explicitly take an adversarial role in a group discussion, and it improves the resulting group's intelligence. The difficulty is that you need to do this in a context where the group consents to this, and with a fairly explicit discussion in advance of boundaries. It also helps to be able to ask the adversary to step out of the adversarial role and clarify their position.