@gyor hear that? Maybe we should slaughter the Forgotten Realms...
Hey, I was one of the few FANS of 4e Realms. When I say I'm all for slaughtering sacred cows, I mean from a creative standpoint. I loved the remixed deities of the Dawn War Pantheon, and it's great to see them carried over here in Explorer's Guide to Wildmount (with one addition - though I get why, since Critical Role has run for YEARS and can't very well retcon it's entire mythology every edition…).
I'm not a marketer though, and clearly 5e is doing SOMETHING right, from a business sense, with its compromise of sacred cows and modern sensibilities.
In Tal'Dorei, they replace the Ability Scores, Draconic Ancestry, Breath Weapon, Damage Resistance and Languages, with a +5 ft speed,non-magical Slashing damage resistance, and +1 Con, +1 Wis. The RAW say that you only keep the Age, Alignment, and Size from the PHB, but that can't quite be right - it would mean you learn no languages by default, at the very least. If it's intended to lack a Breath Weapon, this seems super underpowered, though that slashing resistance is huge.
In Wildmount, Ravenite replace the Ability Scores and Damage Resistance with +2 Str, +1 Con, Darkvision 60ft, and a new additional per-rest feature, Vengeful Assault - Reaction weapon attack when you're hit by an enemy within range of your current weapon. The RAW suggest you keep the Draconic Ancestry for the purpose of the Breath Weapon, since it doesn't say this replaces it.