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.
First, we have these two:
They are strict upgrades of existing cards. Gudul Lurker is better than Triton Shorestalker (in this deck), because you have the option of morphing it. You probably don’t want to do it very often, but sometimes it will be good. Especially if you can fake the next card.
Stratus Dancer has been pushed quite a bit. It has the same casting cost, flight and stats as Vaporkin and Welkin Tern, but it lacks the drawback and has an additional option of morphing it and gaining a huge benefit. In the past, the weakness of this deck was to sweepers, but this definitely helps. You might even use the morph every once in a while, because there are other morph creatures in this deck, and it won’t always be readily apparent that you are playing this. If you play Cloudform, you might even get a freebie, although fitting it into this deck won’t be easy. (Note, if you still want to go ahead an play either Vaporkin or Welkin Tern, play Vaporkin, because its an elemental and thus aided by Master of Waves).
But then there’s this guy:
You just know this card was designed for a very specific thing in mind. It would see play if it was a 3/3 for UUU, but that’s not even enough. Its hard to kill. And, oh yeah, its an elemental, so again, it gains advantage from Master of Waves.
So, a list: