Is [Drakonid Operative] Blizzard's way of saying 'we have no idea how to balance a class so the weak classes get op cards in rotation'?

No. The idea is that Dragons in Priests were never quite as powerful as we had hoped for, and the Blackrock dragons will rotate soon, so Mean Streets was our last opportunity to push the deck for a long time. We didn't want to improve the deck's early game, and the Jade decks are supposed to have the strongest late game, so we made Operative a strong midgame option.

Operative is a class card that you have to build a deck around, so it has quite generous stats. It could perhaps have done the job of 'push Dragon decks before they rotate' at 6/5 or 6/4, but we were more confident in our estimation of the Dragon deck's power level than we usually are, and we knew that if we were wrong, the problem would fix itself after rotation.

If you think 'well Azure Drake is neutral and almost as strong as Operative and goes in more decks so what are you thinking' the answer is that I think Azure Drake is extremely generous, which isn't to say that it should or should not be changed.