1. Bringing back "dTrades" is full of win. This is a genius idea.
2. The site was once mainly focused on Diablo 2, trading, pricing, leveling, etc. Keep the D2 stuff. The dream of many old players was for Diablo
3, i think we will see a return of some once Diablo 3 arrives. Even if Diablo 3 has some type of auction system/ trade system (better than D2), there will still be a need for forums.. whether it be guides, checking of prices, character builds etc....
3. Any other gaming stuff, in my opinion, should not be on this site. There is plenty of other forums (neogaf, gamefaqs, etc.) that people are going to go to talk about other video games. If there is a need for other games / forum for dtrades/postabout, i think it shoudl be related strictly to blizzard games.
4. Facebook is a good idea, some type of integration, as well as an official dtrades page. The only way to get more people to become part of this site is to spread the name, because i think a lot of people have never heard of dtrades or post about.