I don't think it would change my forum visiting activity if trolls all got up and left suddenly. I tend to just read what everyone is thinking on topics without providing much input and just clarifying miscommunication and add neutral facts to help the discussion (or argument) move along as smoothly as possible. I agree with you on the two opposing (but civilized) factions all bringing facts to the table and discussing their views. It's a great way to learn about the topic under discussion.
Plus trolls make for some pretty fun reads. It only sucks when they become over-involved in a thread and practically take over it spouting all they can to support their view and attempting to discredit anything anyone in opposition has to say with little to no info to back it up.
So in short, they're good... in small doses.
