The diplomacy community doesn't really need to be rebuilt, it is good. There are only two real issues
* Most importantly, we need to get rid of the "wait one turn after declaring" rule. I remember when people first started using that rule and the backlash it caused, I actively avoided games that use it. Now it is a standard so I mostly make my own games or play games from players that I know also hate the rule.
*We also have to encourage not only more roleplay, but better roleplay. People who rp in a ridiculous and "silly" way can disrupt an otherwise good game. Players in large slots who don't roleplay or interact not only disrupt a game, but often ruin it. I usually fix this by making sure all the main slots are filled with people who I invite and I have played and interacted with.
other than these problems I do not really see a big problem and I have actually found easier to fill diplos recently than it has been than earlier in the year.