I've long suspected that the new DMG is going to have a lot more "How To DM In <This> Style" features in it, and this further confirms my suspicions. Sure there will be a lot of Canonical/mechanical/Rules guidance. But I think there will be a lot of coaching advice, so-to-speak.
I'd kill to have a DMG that has outside guest "Op Ed" columns and sidebars about DMming, Worldbuilding, Effective methods of Plot-hooking, How to prep your DM Satchel, etc. It would give it a touch of the Best of Dragon in it. I just wish that I knew of more of the creative community being involved (Mastering Dungeons, SlyFlourish, the Dungeon Dudes on the YouTube side of things, would be nice votes).
Additionally, aren't they putting some setting material in this? Maybe they're contributing to that.
Who knows? Maybe some of them are, and just haven't said anything yet (fingers crossed, but not behind my back).