Since it's a migration proposal and the site already works, I believe it already has the critical mass to be a successful SE 2.0 site. I get answers faster on SharePoint Overflow with regards to SharePoint questions then what I do with the Trilogy.
Also, anyone that deals with SharePoint on a daily basis will tell you that often a problem covers more then just one level of running SharePoint. A development problem can quickly be a server problem etc.
Have a look at the existing site to see for yourself SharePoint Overflow
Some existing stats: The site already has 3500+ questions, and a 49 pages of users. That's more then some of the sites that have graduated has had to date.