That does seem to be an excellent middle ground. The pseudonymity would eliminate the element self-censorship that the Techcrunch article seems to be hinting at, while the threat of banning combined with the high cost of creating a new Facebook account would (hopefully) still suffice to keep the discussion reasonably civil.
As a cryptography researcher I've come across numerous cumbersome anonymous reputation systems, but it didn't occur to me that Facebook is in a position to roll one out right now with a minor change if they chose to. The caveat, of course, is that it is centralized and controlled by FB. Whether they have the incentive to implement it is an entirely different question.
"As a cryptography researcher I've come across numerous cumbersome anonymous reputation systems"
What's the best one you've come across? The only way I was ever able to dream up was basically requiring an iris scan to create a new account, but then not connecting the iris data to the account, just using it to ensure the user couldn't create a second account. This may actually be feasible now that every laptop has a built in camera and the patents have finally expired, but at the time I wanted to create this it wasn't yet possible from a business perspective.
As a cryptography researcher I've come across numerous cumbersome anonymous reputation systems, but it didn't occur to me that Facebook is in a position to roll one out right now with a minor change if they chose to. The caveat, of course, is that it is centralized and controlled by FB. Whether they have the incentive to implement it is an entirely different question.