The entire website is implemented as a service. Basically, this means with enough time, you can write your own user interface (like he has) and view bungie.net however you want (think the Reach Stats API, but for everything). Daz couldn't really do what he's doing unless we already implemented this service layer. That being said, the old style isn't coming back in a Bungie supported fashion.

I have no intention of getting rid of it. Bungie.next itself uses the service to render its pages. So does the mobile app. It exists because we wanted to have both our web and mobile clients talk to the same backend. Using it is waaaay better than the old way of modifying our UI - that would break regularly. This service is unlikely to have breaking changes very often.