Wizards seems to always do this: There are decks that are really strong for a season. Then, after rotation, these decks are taken apart. They lose a number of key cards. But then, after a couple of sets, when rotation is once again closing in, they give those decks a second window.
In this case, Monoblue Devotion is getting a few minor improvements and one huge jump ahead.
Last time I had a real point about what’s wrong with the design of Sidisi, Brood Tyrant from a flavor point of view, even if it was written very tongue-in-cheek. This time, not so much. Still written tongue-in-cheek, but this time I can’t really fault any one for the possible problems. There’s just too much history to take it all into account. And I like Devotion as a mechanic.