Interesting to read this back after some time. I've had a downtime in games and do not check the forums often. My question would be: is there anything we can do? Yes, the forum culture will change, and yes: new and young players will be abundant. Perhaps this is the price to pay for the increase in enthousiasm for the game of Diplomacy. Before of 2008 I never even heard of this game, while you grow up with games like Risk and Monopoly. Diplomacy is an 'old man's game', with relative few but dedicated player - at least, I imagine it to be so. Right here and now, "we're witness of the birth of a new age", internet diplomacy via FB, WebDip and the despised playDip - making the game accessible to a great host of online gamers.
Sadly so, the highminded discussions will either be disturbed, belong to the past or must seek new platform in a more private scene (for instance, an email game). The forum is now a wild ground with an occasional troll. I myself remember discussions going too fast, lots of people with opinions. That said, a real discussion will continue, and on a very high level, in spite of the chit-chat in between. I've learned much and was always surprised at the high level of discussion here.
Lastly, adapting the forum might help. I don't think parts of the forum will die when that happens. The community is simply too big to let that happen.