The devs sorta tried this. Last Christmas, I think. Or the Christmas before that?
Whenever it was, they let players dick around with something like the original weapons and XP system of the mod for a few weeks. It was retarded and we all quickly remembered why things changed the way they did.
As has been mentioned in other threads, again and again, there are things different between now and then that go beyond simple mechanics: the number of people playing, for one, and the quality of those players. You won't see cRPG be anything like it used to be. The closest you'll get to the old cRPG is when Battlegrounds comes out. Then, if it's successful, you'll see something like the old cRPG, because in addition to a change in mechanics you'll have a change in the playerbase: it'll be bigger and noobier. Put simply, it'll be healthier and more vibrant.