Unfortunately, I get the feeling that the statement Yoshi P made at one point about content like the Diadem (or was it PotD?) & ARR stuff (& how to make it "relevant again") is something they apply to lore we've "already learned": he said that they "don't focus on past content, they move on and learn for future content." I remember someone linking to it on a Eureka thread when someone was complaining about why they didn't just revamp Diadem to a 3.0 version instead of giving us Eureka.

They do a relatively decent job of tying the MSQ content into stuff you learned in the past, because they plan 5 years out, so when you learn something now that makes you go "oh!" later, that was intentional. But as for going back to revisit stuff like old races and things of that nature, I feel like they're more interested in giving us "new shinies to attract new players/keep our attention" than flesh out old content. Sometimes I even worry that Thavnair is going to be a case of "we already learned a little bit about it so people would be bored now, let's go some place new" which is sad, because I've always been interested in it.

Maybe I'm wrong, and maybe they've softened that stance - we've seen enemies from Lost City hard in the ShB trailer, which means a harken back to the war between Amdapor and Mhach, the War of the Magi (although given that this was the birth of a calamity and that's the whole focus of the MSQ, maybe it's a one off.)

But my gut says that whenever they feel people's interest waning, we'll just get something new, and they won't go back to the old stuff. Which is a shame.