We've always said that details can and likely will change over the course of development. This happens to be one of those times.
Originally, we did want to give players this opportunity. We didn't want to invalidate or take away player options. However, it became increasingly evident through testing that artifacts of the old itemization system could become overpowered through enchanting, especially so with certain items. This is why testing is so important, and it was a decision that took some time to make.
I'd also like to throw out there that some players seem to think this means you can't enchant level 1-60 items at all, when that isn't true. Items gained prior to the 2.0.1 patch hitting the live servers will be unable to be enchanted. Anything you gain after the patch launches and before the expansion, however, are eligible to be enchanted.