Well, if you dont think there is any difference between when zones were illegal and when they became legal, I guess there is no difference.
Well... without having read the article, it's a lil' difficult to comment. But wouldn't the fact that zone D's limit them - and are now legal, be one reason why the 'very-big-power-center' is disappearing?
http://with-malice.com/ - The half-crazed ramblings of a Lakers fanatic in Japan