I agree that this is an issue that requires addressing, but I think attempting to solve it by linking accounts to government issued ideas is beyond terrible. If any such measures are taken, I will be following the fork of the blockchain where the users who refuse to implement it reside which will arise from the inevitable chain-split.

1. In this day and age, forged government ID documents are trivial to obtain on the deep webs in this day and age, so this solution would only prevent casual scammers like the one you caught, but no one remotely determined would be significantly impeded by it.
2. I don't see the significance of your response to @xaero1. True, steemit is a blockchain, and anything submitted to it will remain on it forever - such is the nature of the technology. But this is already for the most part true of the internet as a whole - once something is uploaded anywhere on the internet, it becomes distributed and essentially impossible to remove. Even if you remove the offending revenge porn/DOXing from the original location it was uploaded to, someone will have saved a copy and it will be uploaded again elsewhere - and that's in addition to sites like archive.org and google's automated caching mechanism retaining copies. This problem is not a problem that can be solved with more of the same kinds of regulation, but rather something society must adapt to and learn to live with. Stagnant water breeds disease.
3. The harm the censorship resistance of the platform would be tremendous. You are essentially proposing that a centralized entity retain identity records of users that can be linked to their profiles. Such an entity could be compelled to reveal the identity of a user by judicial order, resulting in a chilling effect on free speech across the board, turning steemit into another panopticon like facebook.
4. Even if the entity is outside of the jurisdiction and reach of a government that is upset with content one of its citizens posted, assuming the records are digital, they could be stolen by an oppressive government's hackers. People could lose their lives as a result of such a measure.
5. This would create yet another central repository of documents that could be used for identity theft that will have a giant target painted on it.

This issue neads to be dealt with the light touch of better enabling self-regulation, rather than the typical heavy handed authoritarian approach favored by statists.

The creation of a secondary voting mechanism may be a viable solution. If a user believes a post to be suspect, they could vote to delay the payout, and share their suspicions in the comments. If others decide they share in the suspicions, they would add their votes to it giving the community more time to thoroughly investigate and withdraw their upvotes if necessary.

I applaud your investigatory efforts in catching that impostor.
Upvoted and resteemed.