In the first screen shot, something I thought was interesting was the bold text in the right column - "players must agree how they are going to select their armies, and if any restrictions apply to the number and type of models they can use." This seems to be GW's spam clause, and interestingly, a rulebook line to cite for banning portions of these unrestricted army selection rules. Again, this is just a snippet, but interesting.
Next is a peek at the basic force org. chart, and the first of the Restrictions and Benefits to taking a "Battle Forged" army. Interestingly, the Restrictions mention all units being of the same faction, or having no faction. I might be reading too much between the lines, but it feels a bit like it's reopening the possibility of a Mercenaries faction that can be added to any detachment. The first benefit shown to taking the force org is that the warlord can reroll their warlord trait.
Next up is a screen shot of the Core Detachments, which can be taken in any "Battle Forged" army. The biggest thing to note here, and the only change, is that a Lord of War slot is included in the "Combined Arms Detachment," which is otherwise the old standard force org chart.
The next screen shots show the benefits of taking "Battle Forged" armies. The first was already shown (reroll Warlord Traits), the second is the big one - all troops from the detachment have the Objective Secured special rule, same as the Skyblight Gargoyles, meaning they can only be contested by other units with the same Objective Secured rule. Note, this appears to apply to Troops from the Allied Detachment as well.
Next is a partial view of the "Unbound Armies" rules, which appear to be just that, with no limits. This is followed by some discussion of Formations, and in the video Jervis promises more formations will be released. The text is partially cut off in the screen shots, but it appears that units from a formation will benefit from the Command Benefits for Battle Forged armies, meaning Troop units in formations will still gain the Objective Secured special rule. That said, there are pieces of the text that are cut off that could counter that.
This seems to be just the tip of the iceberg, but it's also one of the major things GW seems to be focusing on in publicizing the new edition. At this point I am confident that there will be other rules changes throughout, but this might be the biggest one. As a tournament focused player to some degree, I am curious how it will play out in the competitive environment. But, in the end, we will have to wait a few more weeks to see.