Reboot, Reset, Reimagine

With the release of "Van Richten's Guide to Ravenloft", WotC have now published guides to three of the 'classic' D&D settings (if you count the "Sword Coast Adventurer's Guide"). In each case they've taken a somewhat different approach to the material: the Forgotten Realms is essentially a continuation of the ongoing lore, albeit with a quasi-reset from the 4e material; Eberron is once again presented essentially as-is; and Ravenloft has been reimagined for a new era (and to remove some problematic material).

So, what to do for the other settings? Here's my recommendations:

• Greyhawk: I would be inclined to present Greyhawk essentially as an historic artifact - reset it back to the state at the end of 1st Edition (that is, before the "Greyhawk Wars"), explicitly don't include homes for Dragonborn and Tieflings, and lean very much into the "Appendix N" derivation of the whole thing. That means it is more than a little rough around the edges, but it does also mean it has something to distinguish it from the Forgotten Realms, which any sort of an update is likely to lack.
• Dragonlance: This setting suffers from a huge focus on the War of the Lance and, even more specifically, the Heroes of the Lance. For a new version, I would be inclined to reset this setting back to those Wars, but remove the Heroes - the campaign is about the PCs and their place in the war. Crucially, the setting would be almost entirely focused on the War of the Lance - while other settings may have wars, this is the one that is about an all-consuming war.
• Dark Sun: The 4e version of this setting more or less did what was required. There are a couple of further tweaks required, mostly surrounding the issue of slavery, but I would build on what has been done rather than re-re-imagine it.
• Spelljammer: I would essentially just republish this setting as-is. Though I would de-emphasise the links to Greyspace, Realmspace, and Krynnspace, while also putting in canonical links to those settings that came after.
• Planescape: Other than merging some elements of the classical Great Wheel with the 4e World Axis, and resetting the setting prior to the Faction War (albeit, perhaps with some different factions), I would largely leave this one alone.
• Birthright: This setting I would reimagine to be closer to "Game of Thrones", and probably aim at a significantly older audience as a result.
• Mystara: Unfortunately, Mystara is all sorts of problematic - too much of the setting is based on real-world cultures with the serial numbers filed off, in a manner that simply isn't acceptable these days. So, much as I hate to say it, this is a setting that I would leave fallow, except insofar as it can be stripped for ideas for other settings (such as, for example, Glantri).
• Al Qadim, Maztica, the Horde, Kara Tur: Technically, these are all parts of the Forgotten Realms. As with Mystara, they're all problematic for real-world reasons, and are probably best forgotten.
• Taladas, the Hollow World, Jakandor: By this point we're getting into very obscure settings (and, incidentally, Taladas is technically part of Dragonlance and the Hollow World is part of Mystara). My expectation is that none of these would ever be revived, but if they were I would be inclined to recast each as a transplantable setting component - divorce them from any existing setting but instead present them as an area that can be dragged and dropped more or less anywhere.

And that is about that, really.