Also, based on the upcoming new movie and Pikachu Short, there have been no implications of a second new Eeveelution; CoroCoro itself said that in next month's issue we'll learn more "secrets" about Sylveon ─ no hints or silhouettes were given to imply there would be another one coming. I'm not saying it's impossible for them to pull out another surprise and say, "Surprise! Here's another Eeveelution for you, and you, and you too!" but I'm doubtful.
Not to mention, each new Eeveelution has so far been based off of one of the eight "special" types, with one remaining (Dragon). Now we've been given exactly one new Eeveelution. A possibility to finish what they started? Maybe. Although there is reservation due to it not appearing very dragon-like.