I think, like with Mythic+ Dungeons, there’s something to be said for consolidating the raid difficulties by lowering the top and raising the bottom.
I think there’s also something to be said for reducing the length of the individual raid and having more of them.
Signing up for a raid with 10 bosses is a more time-consuming endeavour than signing up for one with 5.
I also think the Mythic+ Dungeon approach to difficultly, where you add affixes to make it harder, would work nicely for raids as well - instead of relying on arbitrary adjustment to mechanics and health.
You removed LFR but then turned Normal in LFR which I’m not sure makes sense.
I see a need for:
Story Mode to complete quests and see the content (at least once).
Casual friends & family guilds lower / mixed skill levels.
Challenging raiding for more skilled players.
RWF showcase.
Currently 2 and 4 are being served reasonably well but 1 and 3 are not.
LFR is a bit too difficult for Story Mode. I know they’re adding in a specific Story Mode for final bosses but this is just one fight and won’t show the whole raid.
Heroic is not challenging enough for organised guilds but Mythic is too difficult (logistically and tuning).
So rather than this new Story Mode final boss just make LFR a bit easier and reduce the rewards somewhat.
Normal is probably fine as is, it fulfills its purpose.
Make heroic 10m and 25m (as fixed raid sizes make it better for tuning difficulty).
Tune it up a bit. Make this the goal most raiding guilds want to achieve.
Make Mythic for RWF only. Once this race is finished Mythic is done for the season. Remove all rewards from here. This is a showcase for Ultra organised guilds, similar to what we have now.
Edit: My remove all rewards I meant gear. Have prestige rewards, tabard, title, maybe a transmog or similar.
I had posted this in another thread, but I think that a slider difficulty of Heroic Raiding, with additional rewards of course, could fit such a bill. For example, at the entrance of the raid there could be an NPC where the raid leader can select the HP and Damage scaling of the bosses (0%, 5%, 10%, etc. up to 50%?), with increased number of gear drops (but not of higher item level!) and with increased currency drops the reward for the extra difficulty.
That way guilds that want a harder-than-heroic difficulty but don’t want to have to deal with the immense mechanic difficulty of Mythic would have their outlet.