I am a player that has played classic and several expansions and returned to TWW after a longer pause. I noticed some things feeling strangely off and think this could be easily improved in upcoming addons:
Character progression feels not good. As a new player you are kind of pushed into playing delves, which are great fun for a while and offer lots of challenges. You get champions gear by doing delves and occasionally even hero track gear (from the card extra chest) and you get free 616 ilvl gear through the weekly vault drop.
After being geared well after a few weeks into the game and delves getting shale, players will look for other things to do and improve the character even more, but there sadly are only few options available anymore at this point.
Playing heroic dungeons will get you nothing useful, not even the correct crests you need at this point, making heroic dungeons useless to play. And heroic dungeons are also not much fun, as they are much too easy at this point of character development.
The same is true for LFR raids, which do not give you anything worthwile, besides low level crests that can be exchanged 90:15 (which is not worth the effort). In normal raids (which already start to feel equally different than level 8 delves e.g. at some encounters), you still only get very few useful item upgrades and only a few runed crest per week on the 2 hardest bosses.
Silken court normal in an average pug group already feels harder that all level 8 delves, which feels to make not much sense if you look at the potential rewards.
For all those activities, the weekly vault rewards are also much too low… they dont nearly reach the 616 ilvl of the delve weekly rewards, while the needed effort to clear those raids feels much higher overall than just running through level 8 delves in <20mins without ever having any real problem in them (especially having a leveled up Bran available after a few weeks).
And even in heroic raids, the average item rewards are better, but not nearly as good as one would expect considering the difficulty level - especially in pugs (which i take as comparison, as delves can be played alone, without a guild raid group, as well). This feels extremely off, especially for pug road-block bosses like Silken Court.
And after having finished a whole heroic raid, which takes quite some time and is clearly harder than running through level 8 delves alone, you end up with ilvl 610 rewards in the weekly vault for some reason… still leaving the 3 delves weekly rewards better.
This makes no sense at all from my point of view and feels completely off.
I cant say much about m+ (which dont seem to have the same problems, at least in the weekly vault), as I think those 30 minute rage fests are not fun at all, especially as healer.
Conclusion
It would be much better imo to have something to do after having finished delve content and getting most useful delve item upgrades, that is not high m+ or heroic+ raiding to get further, noticeable character improvements. In the moment, average players will be more or less locked into delve content which gets stale quickly (being solo content contributes to this noticeably) and having only those few (usually stressful and in comparison not that fun) activities left, that also are harder to do in pugs, is not very motivating long-term.
Delves should clearly be positioned below heroic raiding (which should be made harder) to not have that much content skipped (like heroic dungeons, LFR or normal raiding, which at the same time would be perfectly fitting the skill levels of players just having finished delve content).
I mean… you want to keep players playing and paying each month… so offer them proper content to keep busy please.