there has been a steady shift of population towards mara/jugg/assassin/powertech over the last 6 months or so. 1.3 really started the change, as it became clear which classes would make up the perfect compositions.
no one can *prove* any of the theories that get thrown around on the forums. unless it is something a dev said specifically, it is all conjecture.
After seeing most of what the devs have posted since launch I really wouldn't take what they say as proof that thinks are right.