New RDF system

So I just have seen that they're fixing the RDF system - "Icecrown is being updated with latest fixes including a rework of the Dungeon Finder."
What was wrong with the old one and what is so special about the new system?
Where can I find in-depth changelogs?

In the old one you could barely get a random group if you didn't make a premade group of your own because the matchmaking was bugged I think. They just probably fixed this issue so that from now on you can find groups easier and faster.