This is Mark's 20th (!) anniversary as head designer! He lists out a bunch of highlights and lessons from each of the sets in the previous year, a few that stood out:

• There needs to be more synergy between sets. This has been true since blocks went away and one I really hope they improve upon (or just bring blocks back!).

• Many players liked having a set (Brother's War) that looked back at one of Magic's greatest stories. "Players liked seeing old characters they recognized in card form.... They also liked how the design made the artifacts feel like a throwback while still applying modern design technology."

• The Transformer cards (in Brothers War) felt out of place. Happy he identified this one. "[T]he core of the set for many players was nostalgia. These players felt seeing cards of a different IP flew in the face of that."

• All of the lessons from Aftermath! Set was too small, most (all?) players didn't like paying the same amount for fewer cards, the set was sold as story-focused but not much happened story-wise, and many players were unhappy about Planeswalkers losing their sparks.