Also is the Dragon Isles the only zone remaining that had some work done during Vanilla development but was scrapped/never released/expanded upon. I guess there was Emerald Dream zones but we did get Emerald Nightmare (still emerald dream might be possible again). I also remember Outlands had some development done during the original launch and a few other zones had some references in files IIRC but were eventually released.
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Also worth pointing out we still don't know what "The War" the Blingtron reference (https://wowpedia.fandom.com/wiki/The_War) is about or where it is.