Still, they could have a small announcement somewhere in their main page or something. Well, in any case, the information travels quickly on the internet era.
Oh, one more thing that affects Lizardmen a bit: When used on cavalry models, the Regrowth spell resurrects one model for two wound rolled (previously it was one per one for everything).
What it comes to Tomb Kings, yeah, the people at their forum are ecstatic. Not only Crumble prevents overrun, but their own FAQ changed the Entombed Beneath the Sands rule so that those units can deploy normally. So in the future you might see Scorpions and Tomb Swarms as War Machine protectors as in the previous editions and maybe even a big unit of Stalkers acting as a make-shift Volley Gun (with a really short range).