Managed to catch some of the live twitch session. Sounds like they have revamped lots of rules (and my first impression is for the better).
Examples:
Versitle: can now engage in hth at the weapon’s Melee Range
Blast: Models targeted by blasts potentially increase their armour save if they are in cover.
Blaze: reworked so you run around on fire before being pinned (much more fun!)
Other stuff but can’t remember most of it, looking forward to the book for sure!