Ahh, right! I don't keep up with Viz.
How likely would a Bluray of the 90s be after they decide to air a HD remaster? Why not just wait for a Bluray if they make one, since they did that with Crystal?
I don't know enough about Japan to comment on the likelihood that they'll release Blu-rays of the 90's anime (assuming they really did find a source for that). Since it's 200 episodes, maybe they'll stick to HD streaming. I don't know. I've heard that the market for anime in Japan is difficult these days, so publishers like to abuse their fans (with high prices and low episode counts), and they try to abuse foreign markets so that Japanese fans can't easily escape the their bad treatment by importing.
Viz got the rights to the 90's anime and Crystal, and they decided to re-dub the 90's anime, and once they're finished that they intend to use the same voices to dub Crystal. That's why they're waiting to release Crystal.
Toei gave Viz DVD masters for the 90's anime, and Viz said that DVD doesn't sell anymore, so it must be Blu-ray. Then Viz said that true HD for 90's Sailor Moon doesn't exist anymore (apparently they asked, and Toei said so). So Viz is "upscaling" DVD to Blu-ray. Viz also did a bad job on their DVDs.
Madman Entertainment in Australia got the Australian rights from Viz, and they said that they
want Blu-ray, but they're not going to touch Viz's upscale. If it's not real HD, then there's no point. And Madman is going to re-do Viz's work on the DVDs, because Viz did it wrong.
If it's true that Toei just "found" the HD source for 90's Sailor Moon, then Viz is going to be in trouble and I don't know what they're going to do. They should scrap the entire project, release Crystal on Blu-ray for now, and wait until they can do the 90's Blu-rays the right way. But Viz is not going to like changing their plans like that. It will cost them money, and they've already been trying to ignore mistakes and keep on pushing forward.
If this new HD source is real, Madman in Australia is going to wait for it. They're not going to follow Viz down a bad path.