"a strict NO Offtopic rule and this forum flowed beautifully."
That's not true at all, Dave. I know you guys like to use the "good old days" idea as if it were a time when every thread was bursting with interesting AvP related discussion and there was no off-topic talking ever, but that's just because it happened a long time ago and you remember it fondly.
http://www.avpuniverse.com/forum/610.html Thread about joining a clan and how Dave got his avatar
http://www.avpuniverse.com/forum/533.html Thread about Alien Resurrection and Jurassic Park
http://www.avpuniverse.com/forum/462.html Thread about how something has already been discussed
http://www.avpuniverse.com/forum/562.html Thread about crossovers
I did not pick these ones out, I clicked four random threads on the last page of the forum. I joined the site about a year after it was made and there was already an official off-topic thread, but there were plenty of on-topic threads because for about two years after the site was created we had lots of movies, books, comics and games to talk about. But we were all kids and enjoyed debate in a whole different way than we do now. The problem is not that the teenagers joining the site nowadays add off-topic discussion to the site, the problem is that we're not teenagers anymore. We're too old, we have college, we're in the army, we have jobs, we have stressful lives, we can no longer appreciate this community like we used to and we expect our overinflated standards to be met by something that has never existed. This site was NEVER what you like to think it was. WE were different. And now we're old people in charge of a kids' playground, telling them how to properly slide and swing and build sandcastles.
And you, Dave, are the worst kind of old person, blabbing about how awesome YOU were, because you didn't have such luxuries as an off-topic thread back in your days. But back in your days, you joined off-topic talk freely and now a member gets a warning for a single off-topic post. So new members will stay safely in the off-topic thread for fear of getting warned. But yes, take away the off-topic thread and tell the members to discuss AvP related things only. And then they'll make a topic about why aliens have have such long tails and we will say "We've already discussed this, it's because (insert long, complete explanation here)" and the thread will end with the second post saying "Oh, ok." So the new members won't make any more new threads because they only want to discuss things we've already discussed, but don't worry, Prometheus will come out and we will have about a month of discussion until we've talked about everything and then the site will go to sleep again.