I think a new edition of D&D is inevitable. As opposed to discussing that possibility I would ask:
What do you think it will look like based on current trends?
5e was an entry point for a large number of people into the hobby. As a result, its prioritization of (player-facing) simplification was very useful. Now, however, I believe it is becoming a stumbling block. People are only "new" for a little while--perhaps a few years at most. 5e lacks for mechanical things to sink your teeth into; one of the
only criticisms levied against it (relatively) early on was that it lacked for customization options relative to previous editions.
So: I think the pendulum is swinging back the other way. I'm not saying it's going to become like 4e or (God forbid) 3e, but I absolutely think that there will be more feats and SOME kind of change in terms of class customization beyond the limits we currently have. One likely option, I suspect, is to blend together the concepts of subclasses, prestige classes, and Paragon Paths, possibly including Epic Destinies as an endcap development phase beyond level 20.
Because subclasses are popular, but I think all of us can pretty clearly clue into the fact that they run out of steam by level 12+. Hence, having higher-level "Specialties" or the like would be a great way to add more customization, without inflating lower levels with a ton of choices. Likewise, I suspect we're going to drift back to the 1 feat at every 3rd level + 1 Epic Boon at 20 + 1 "Origin" feat.
Origins are likely to get some attention too. They're popular, but they're pretty...lean. I could see them becoming a bit more hefty, as long as really Simple Straightforward options remain right at the top and reasonably balanced.
On the subject of balance: I've heard from many,
many 5e GMs at this point that they wish the system had their back more--that they didn't need to be so
constantly thinking about escape hatches for the situations where a combat (or even non-combat!) went completely pear-shaped in either direction and produced something that just wasn't fun. That doesn't mean becoming 4e (that's never happening), but I definitely think that a
greater concern about balance in 6e's design is functionally guaranteed. Again, this is not going to become 4e, whatever they do is supremely unlikely to please me on that front. But actually caring about it
somewhat is likely, whereas the designers of 5e clearly couldn't give two poops about balance most of the time.
Lastly, I expect a greater variety in classes. The core exists and is good. Players are looking to branch out, and if the core of 6e doesn't support that, folks
are going to ask, "Is it worth sticking with D&D when I have to re-learn it? Or would I get more out of something else?" Netting
this many people over ~15 years means you have a lot of new blood that needs to be
kept if you want them to not drift away, and their interests are nearly guaranteed to be quite a bit different from the grognards and victorious edition warriors whom 5e was specifically written to court. 3e-derived rules are
very unlikely to be nearly as popular among the current userbase compared to what they were in the past.
More or less, I'm expecting a regression to the mean. Something a little bit more like 4e, with a bit of the variety/diversity of 3e, and a hell of a lot more focus on "make the GM's job MUCH EASIER" rather than on "presume the GM knows everything and can fix everything and just make rules that sound nice".
It’s fine saying what you hope for, but what do you think the reality will BE?
See above.
I very much do think that it's going to become a small amount more like what I hope for. But I also think it's mostly going to become a representation of the
reaction to 5e over time, which is only partially in alignment with my interests, and partially against them, and partially orthogonal to them.