A quick summary after watching 2/3 of the video:
1. Adventures. Will include 5 short "adventures", most are about a 1/2 page.
2. Greyhawk. Greyhawk treatment similar to the original Gazetteer. Focuses first on the City, then describes the wider world, references adventure sites. Also references potential bastion sites.
3. Lore Glossary. Includes info on key legendary figures, like Modenkainen, or sites, like Balder's Gate, or materials, like mithril.
4. Bastions. Players can establish a bastion at level 5. Acts almost like an NPC, PC's can send orders (don't have to be present) to it to craft, farm, etc. on the bastion turn. Can combine bastions from multiple PC's. Portrayed as a player's opportunity to DM their own mini-world that they control.
5. Magic Items. Biggest chapter. Revised and added many. Much more artwork. Added the magic items from the D&D cartoon. Applied magic effect types to more weapons (i.e., flametongue can be a great club). Added prices to the items, as well as crafting rules.
6. Tracking Sheets. Downloadable. Way to organize and track your DM/campaign info, like NPC's, settlements, bastions, magic items, party composition/backstory, conflicts, and session planning.