Citing Classic (subject of 'you think you want it but you don’t) is a perfect example of why Blizzard never says no to anything anymore. Here you are taking the most infamous time they said no to something, only to backtrack on, and using it to suggest that their minds can be changed. That should really inform you thinking on the tweet you quoted above.
Of course on the topic of playable Alliance High Elves they have said no for longer than they did to Classic, so that is something to bear in mind.
Frankly I wouldn’t be surprised if High Elves for the Alliance ARE in fact added as part of the now widely expected Classic+ (probably announced at Blizzcon next year) but Classic+ won’t be retail, won’t be the ‘one true timeline’ and will be a different game overall.
People who argued against Demon Hunters did so because Warlocks had been built using components from Warcraft 3 Demon Hunters, particularly Metamorphosis. Blizzard had to demolish the Demonology spec and rebuild it from the ground up to create design space for Demon Hunters, so scepticism at the time was warranted. Transforming a class is expected though, even if the scale of the Demonology rework was considerable at the time. Note what they did they do, they had to take the substance of the spec to create the class. Are you suggesting they take the substance of an existing player race, Blood Elves and change it into something different than what Blood Elf players signed up for to faciliate the introduction of Alliance High Elves? Because that is the equivalence of the example you are using.
And cross faction play took the game nearly burning down for them to take a look at their core assumptions and reassess, the same process of reassessment that led to Void Elves getting those normal skin tones to enhance the compromise. The dumpster fire of Shadowlands caused a lot of hard rethinking but while they moved on so many different issues, they never actually moved on Alliance High Elves, did they?
Draenei weren’t announced at the TBC reveal because Blizzard changed their minds about adding Pandaren and extra time was needed to create a new Alliance race. This delay is almost certainly responsible for the delay in announcing Alliance Shamans and Horde Paladins…
As for the idea that they are saving a High Elf announcement…which seems to be the last refuge of the damned here…
The Draenei were revealed in May 2006 and the ending of Paladin and Shaman exclusivity was announced barely two months later. One was clearly delayed by the other. Hard to announce Draenei are getting Shamans if nobody knows what a Draenei is.
Augmentation Evokers are a unique experiment, I do not see them as a precedent. The Evoker class was the big headline feature of Dragonflight after all.
As for your scenarios where the debate ends, 1 is likelier than 2, because 2 would need them to ignore why they created Void Elves in the first place, why they gave Void Elves all those incongruous customisations and to place as much weight on an adjective as those seeking High Elves do. After all, Void Elves already HAVE High Elf customisations…they just cannot make other people agree that they are High Elves (bleeding purple and being engulfed by void every 30 seconds does that).
I do expect High Elf narrative content in Midnight, even if that content is to do Veressa alone in Windrunner Spire or interacting with her sister. But I actually don’t expect them to have a major focus unless that focus IS on their retirement from the scene in some fashion.