The article was like a summary of the collective thoughts of The Mana Drain for the masses. Go forth, our emissary!

Anyway, I was looking around for other ways to abuse DD other than Stage, and I was surprised at how very few cards there are that "become a copy of" something once they're in play. Only one page on the gatherer. I agree that this new rule suggests exploring that space much more aggressively.
On balance, I think this is a great change. Mechanically it doesn't close any doors, and it's opened a bunch of new ones. Good show, WotC!