The cards we are most comfortable releasing at an intentionally high power level are class cards that require a deck to be built around them. Operative reminds of a safer Goblin Blastmage. Blastmage and Operative are extremely similar in that they only go in one deck (Mech Mage, Dragon Priest) and both have intentionally high power level because of this drawback. Blastmage was arguably higher power level, in a more aggressive deck, and was still a card I think we look back on as a success. A (4) 5/4 or (5) 5/6 are pretty bad in constructed, but if we can make you look at the text box of a card and motivate you to build your deck differently to take advantage of an 'unfair' text box it feels like a win. There is a balance of course, every game shouldn't feel like you won or lost because of one card you drew or didn't draw but I don't think cards like Operative or Blastmage get there. Reno is much closer to that but I would say Reno has gotten more positive than negative feedback overall.

This is all to say the most powerful cards in a given set are likely to be cards that are only powerful in 1-3 decks. We haven't always hit that mark in the past, but that has been a goal for quite some time now. For Operative in particular, Dragon Priest gets hit fairly hard by rotation. That in combination with how much data we already had on the Dragon Priest kit going into MSoG, we were very comfortable releasing a Blastmage-like buildaround card for Dragon Priest to use.