Structural but not systemic.
They'll incorporate the revisions to the Variant Class Features UA, maybe include a few more "best-of" archetypes from Xanathar's, include all the latest errata, and give the books a sweet new special cover that's different from the holiday 2018 covers so I'll have to buy them all over again.
Oh, and Aasimar & Eladrin in DMG will be changed to their VGM and MOT incarnations.
I'd LOVE for them to include Goblinoids and Orcs in the PHB as those are extremely popular races that show up in pretty much every game as an antagonist race, but I doubt they'll do so. If they did, I would expect the E:RLW/EGW stats for Orcs to show up, as opposed to the VGM version with racial penalties.