Well if they actually planned these things they could go like Paizo. When Paizo stop using a D&D-ism they already have another term ready to go. But WoTC are by nature reactionary, not really forward-thinking. Half the time they don't even understand why they stop using a term beyond "the...
So weird, since posters here were saying half-orcs and half-elves still existed in FR, it was just that they would now be mechanically represented with the full-blooded ancestor's stats, but now it's all gone Damnatio memoriae.
They didn't leave twice. They stopped listening to prayers once (but were still there) and the second time Krynn was the thing that was removed. The gods stayed where they were.
I never understood the "Dark Sun is future Dragonlance" angle. There's literally no common touch points at all, the maps share nothing in common. Dark Sun has halflings as a big part of its setting, whereas Dragonlance bans them.
The only commonality seems to be no orcs.
The biggest issue I see is that all 2E settings share a single unifying aspect: they broke the rules of 2E to deliver a truly different experience. 5E designers don't want to do that, cf Crawford's maxim of "D&D is D&D".
ASI should have been removed entirely. "Here's a few extra points...because."
You have stat buy points. Just raise them if you think its not high enough. The way it is done now is silly.
The Northern Ergothians were not the main citizens of Ergoth pre-cataclysm. That was the people of Southern Ergoth (around the capital Daltigoth), who looked different. The northerners became dominant because they were the undestroyed province of the Empire.
The southerners looked like this: