Magic hasn't gotten as far as it has on the strength of its gameplay alone - although that is the major factor. The story and the background lore play a big part of the appeal for many people. And while some purists say the best days of Magic's storyline are behind us (with the Weatherlight saga long having ended), and the quality of Magic fiction has been mixed over the years (though thankfully nothing of late has been quite as bad as, say, the Legions and Scourge novels), Mark Rosewater has opined on his Tumblr blog that the stories of upcoming blocks are particularly great.
When adventmtg said, "I've been playing MtG since 95 and it's amazing that a game I started playing solely for the gameplay has evolved into something that's so engaging from a story perspective. I'm pretty geeked about seeing what happens next!" Rosewater replied:
If only you know how many awesome things were coming your way storywise. : )
And when corfell said, "Magic has, in my opinion, one of the most vast, multifaceted, and wonderfully woven stories ever dreamed by human brains. The promise of even more compelling content reduced me to a content puddle of goo on my floor. Thanks again; to you and all the other incredible talents who have made Magic what it is today. Maybe one day, its stories will bloom on-screen," he replied:
You’re very kind. Yes, if you love story, there is all sorts of goodies in your future.
This is vaguely worded enough to not give anything away - Rosewater is an expert on that - but also specific enough (and it's come up twice in the past few days!) to be notable. Whether this just means Rosewater is confident that the Tarkir block lore is one of the best of recent years, that some favorite characters (particularly villains) from past blocks are returning in Tarkir, or that upcoming supplemental products will have cards for story-only characters, or something altogether different, remains to be seen.