After the release and massive success of Lemuria, it seems clear that revisiting old content is a big success in the game. This was already evidenced by the success of the Catacombs- we saw a great response to the return of Dragonspyre characters and a further filling out of the history of Ravenwood, Avalon, and Dragonspyre itself.
As the storyline moves further and further into more meta-analysis (started by the third arc, with Raven and Spider, and continuing now as we learn that Earth is not in the Spiral, and some questions about its origins), I think it is the perfect time to return to some old worlds and loose ends dropped throughout earlier times in the Spiral.
Example- I'd love to see more about the ancient Celestians. Their continued survival is hinted at by the existence of Qyburn Stellargaze in the Arcanum, and, after all, if anyone is going to understand the secrets of the spiral's astrology and universe (and therefore Earth), it would be the Celestians, wouldn't it? I find it hard to believe all of the Celestians were wiped out by the Storm Titan, given that we know that several of Morganthe's forces survived. We know from Malistaire that the devs love to bring back old villains, especially. Perhaps, as Crystalline Spider Morganthe flew through the sky, she landed on the spacecraft that now houses the survivors of the Celestian catastrophe. We can travel there with Dasein as he explores further the difference between "Good" and "Evil" through the Celestians' treatment of the now defeated and imprisoned Morganthe, filling out more history of what is, to me, one of the most well-crafted world lores of the game.
Another thought is a third return to Grizzleheim. Though less obvious of a return than the Celestians, we know from Wintertusk that the devs are open to returning to the world. The first world added after the conclusion of the first arc, and the only world (other than the clearly-meant-to-be-a-joke world of Wysteria) that has its own completely contained story, Grizzleheim has so much room left to expand. After the conclusion of Arc 3, and Raven's continuing to live in Empyrea forevermore, what has changed in Grizzleheim, her old home? Are the Grendels rising up? Perhaps we can go back to Nidavellir, one of the most beautiful worlds in the game, and go into one of the two doors that lead to nowhere on the lower levels.
Helgrind and Winterdeep Warrens are my two favorite dungeons in the game. They are creative, engaging, and unique, and it's a shame that many players now skip them entirely, choosing to bring a higher-level with them to run Jotun. Perhaps the Ravens can redeem themselves after two stories where they are the villains?
Or, maybe I'm just feeling nostalgic, and the rest of the game would rather have entirely new content than a revival and revisiting of previously created stories and worlds. Thoughts?
I, for one, would love to see more content that brings us back to 2nd-Arc worlds. Celectia is one of my childhood favorite worlds, and Zafaria could really do with some extra depth. And while we're at it, it occurs to me that Khrysalis never got a Skeleton Key Boss, so why not put one in there? I would really, really enjoy that kind of look back at past worlds.
I don't know much about lemuria, but this is a good idea I feel like Wizard city has a lot of potential, maybe I just like the theme of it though. Wysteria was almost another version of it. I am almost lvl 100 right now, and the arc 1 worlds are still some of my favorite
I also love visiting old worlds. I would love it if instead of making a "Fire" area in the new world for the sake of a fire area have us go back to a Firey area, but a new part of it. I feel like there is so much more to explore in many of the worlds that we have been to. I'm ready to be Willkommened back to Karamelle, tour Celestia visit our friends in Mirage and so much more as we continue to learn about the Cabal and Daesin etc.