heros and villains

I think you nailed the three main reason for troll-ish behavior. You're also right that we want to draw a stronger line against attacks, but without censoring ordinary disagreement or criticism. Especially criticism of legitimately bad behavior.

Even when you look at the "no personal attacks" page, they have to clarify "what should you do instead". Trying to find a way to generalize that policy to "no attacks, period", we'd have to outline what people should do instead of making general "group attacks" and battleground behavior.

Yes, you're right, we could have guidelines on how to critize and where.

It would be also useful if there was a safe place for meta discussions. When I say a safe place, I mean a place where you don't disrupt the project and its editors. Indeed I think wikiproject entangles too much those different kind of discussions.