Announcement Week is upon us and today Mark Rosewater kicked things off with a series of changes that are going to drastically alter Standard, Draft, and the nature of Magic sets. The changes, summarized, are:

Starting with the largest change: moving to single large set releases. According to Rosewater the shift from three set blocks to two set blocks showed that the problem was not stretching mechanics across three sets but rather the inability of the small set to meet expectations put forth by their companion.

These stand alone large sets will be drafted as large sets are now. The new structure does not mean there may not be multiple sets on a single world; Rosewater cited Kaladesh as a setting where Energy could be a focal point for two large sets with the supporting mechanics changing.

The reintroduction of the Core Set is designed to help bolster Standard. The set will be approximately half reprints and half new cards, with the latter focusing on resonant cards. These designs will help the set with its intended audience: newer players. There will be cards printed with a focus on Constructed play as well.

Starting with Ixalan, Masterpieces (like the Kaladesh Inventions or the Amonkhet Invocations) will no longer be a regular feature of every set - Ixalan does not have a Masterpiece series.

The changes revolving around the Gatewatch will see less focus on the protagonists of Magic's story starting with Hour of Devastation. From Rosewater's article:

1. We're significantly pulling back on how often the Gatewatch will appear as planeswalker cards. It will still happen when the story calls for it, but far less often. For example, for all of 2017 and 2018, only a handful of planeswalker cards will be Gatewatch members, and that's including in Planeswalker Decks, where they'll appear slightly more often.

2.Our new plan is to continue to design flavorful story cards but only push them for Constructed when, through playtesting, we believe that they lead to a better Constructed environment.

3. The Gatewatch are still going to be our protagonists, but every member will no longer show up in every block. We may even have some blocks where none of the Gatewatch appear, although even those blocks will still be relevant to the larger story.

The goal of point two is to avoid cards like Emrakul, the Promised End from warping Standard. A powerful storyline card, Emrakul proved untenable in Standard.

Finally, Play Design is a new division of Magic R&D that is focused on healthy play environments. They will be responsible for ensuring balanced and fun Standard, Sealed, and Draft. We will hear more from the lead on Play Design, Dan Burdick, later this week. We do know that Melissa DeTora and Andrew Brown have been hired to staff the team.

These are massive changes that come on the heels of another relatively recent change: the original shift to the Two-Block Model. While we will not see the full impact of this change until after Ixalan Block - what will be the final block for the foreseeable future - it is clear that the people who make Magic want to keep the game healthy and they are willing to try new things to fix old problems.