You are probably 8-10 years too late...But I don't believe all of it was due to troll's, shill's and sockpuppet aliases...Much of the exodus has been market related...Let's face facts: there are alot fewer traders nowadays. Many left the game and Elitetrader isn't something that alot of former traders are interested in visiting.
For those who remain, I'd view the "Verified Member" moniker as a non-starter. There are few threads going nowadays and this notion that all of those "former members" are going to suddenly rush back to this site if some form of verification is enacted is delusional...
The bottomline is that this sort of proposition would more than likely drive traffic away from the site as people value their anonymity in a world where holding that anonymity is becoming near impossible. wrbtrader is spot on.