What frequently perceived or cited flaws of 5E do you believe exist for 6e to address? I do not want to suggest that there are no flaws, but I am curious about your own speculative reading of the upcoming Zeitgeist.
I doubt, for example, 6e would go this route due to your aforementioned issues of "too much change" and the "uncanny valley," but I have noticed that a lot of contemporary D&D-inspired games have compacted their total class levels from 20 to 10.* The impetus for this change seems oriented around a growing "new normal" for both the average length of campaigns and the "sweet spot" for balance.
* Though many others also preserve the 20 level structure (e.g., PF2, Fantasy Age, etc.).
I have no idea what WotC would change in a future edition, but here are the things I think are messed up:
(1) Combat: By and large it's pretty good. I think there are a few broken areas, such as attacks made on Bonus actions every round. Polearm Master crossed with Great Weapon Master, I'm looking at you. For the most part, though, it works fairly well. You can tell simply by the length of the sections in the game what WotC focused attention on.
(2) Skills and Saves: While in combat, they managed to implement bounded accuracy fairly well, both skills and saves have issues. They work OK in lower to mid levels, but the scaling starts to break down at the higher levels. This is particularly obvious with regards to saves. Consider that at about 10th level a character who has a strong stat and a strong save has a bonus of around +9 or +10 while one that doesn't have a strong stat and save has a bonus of 0. This means that the first character essentially ignores all low DC threats while the second has about a 50/50 shot. However, high DC threats are essentially impossible for the second character and, without a lot of buffs, stays that way. As DCs get higher, characters gain glass jaws. Similar effects happen with DC creep in skills. At lower levels it's still worth it for many characters to keep trying to do things they're not strong at, but at high levels it's not even worth it. This happens IMO because skills and saves are both binary success/fail situations. One fix to allow DCs and accumulated bonuses to go down would be to make them work less as binary situations. A better skill challenge type mechanic (3 successes before 1 failure, etc.) means things can be more like the combat system. I'd also dump Expertise as written given that it contributes to DC creep.
(3) Missed opportunities: Vulnerabilities and resistances are a great way to encourage PCs to move outside their comfort zones. For instance, monsters that have either resistances or vulnerabilities encourage the character using their favorite weapon or spell combos to try something else. To this end, I'd get rid of the "magic weapons hit everything to get through resistances to BPS damage". This would allow for some upper tier weapons having interesting properties, such as the ability to do two damage types, thus letting its wielder take advantage of vulnerabilities or avoid resistances. Magic armor doing something like this would also be really useful. It lets the bonus not get higher and higher.
I'm sure there are some other things I could think of, but this is a pretty decent start. In general 5E is pretty well done, but it's got some rough patches. This is what you see over time and play.
