Wizards doesn’t have much of a history of banning enablers, and in their KCI ban, they explicitly stated that they think strong enablers are fine and even beneficial to Modern when they appear in/enable multiple decks at once. That’s the case with all the cards you mentioned. More on enablers and bannings in this article: http://quietspeculation.com/modern-top-5-enablers/

Let’s look at KCI, Affinity, and Lantern control…all powerful decks, all attack from different angles, all have had staying power in one form or another, and all have sat atop the metagame for a period of time (albeit not permanently). Looking at these lists, can we really look at Mox Opal and say that there isn’t a common denominator here? Isn’t it fair to at least discuss the banning of this card, given what we’ve seen it do?

I’d argue the same could be said of Faithless Looting. Dredge, Phoenix, Shadow, Hollow One, Bridgevine–given the power level of these decks and the relative staying power (granted, H1 and Bridgevine have dropped off but I’d argue are still relevant), shouldn’t we examine Faithless Looting? Or Ancient Stirrings?

I know that this isn’t a terribly productive conversation to have, after all, all anyone needs to do is point to a card like Lightning Bolt and say something like, “Wanna ban this too?” I recognize that talk like this encourages eye rolling in much of the community, after all only Wizards has the power to do anything about it, so what’s really the point of bringing it up. But I hope that these are the sort of conversations they are having, and I hope that debating these things here inspires debate at the highest levels.