Approaching 2024: Completing a Cycle?
Much has been spoken about 2024 as the 50th anniversary of D&D and, to a lesser extent, the 10th anniversary of 5E. While nothing is guaranteed, most seem to agree that we'll see
at least revised core rulebooks, if not a new edition. Only time will tell. But ten years is a long time without some degree of revamping, especially if we consider history. From the completion of the 1E core line in 1979, we have seen new editions or revisions like so (new editions in bold, revisions in plain):
OD&D 1974 | B/X/BECMI 1977, 1981, 1983, 1991 | AD&D 1979, 1989, 1995 | D&D 2000, 2003, 2008, 2014
Meaning, the previous longest gap was ten years between 1E and 2E, which is the same length of time between the publication of 5E and 2024.
So while WotC has sometimes spoken of 5E maintaining some degree of "evergreen" status, it does seem highly likely that we will--at the least--see some kind of revamping of the core rules; whether mostly cosmetic and minor tweaks ("5.2"), a significant revision ("5.5") or a new ruleset ("6E") remains to be seen (my guess would be somewhere in the 5.2 to 5.5 range).
Regardless, we could look at the next two years--2022-23--as the "completion" of 5E or, at least, Phase One of 5E. If we entertain this view, we can also look at what is missing in the first eight years, both in terms of popular classic themes and rules (e.g. planes, a full treatment of psionics, epic play, etc) and settings (most notably Planescape and Dark Sun, but also Dragonlance, Greyhawk, a full treatment of the Forgotten Realms, etc).
What do we know? Not much, except that at least two more classic settings and three new settings are in the works, although WotC has been clear to say that not all of these may come to publication.