Mythic Dungeons

Finally, mythic dungeons (or rather: mythic+ dungeons) - the probably best PvE innovation ever and the most influential since making raiding available to 10 man-groups.

Multi-wing instances aka mini raids

Multi-wing instances are intended as being something akin to 5 man-raids, consisting of multiple individual dungeons tied together, populated by boosted mobs. There are two sorts of instances already in the game which reflect pretty well how these mini raids would look like: Very long dungeons with lots of bosses on the one hand (with the exception of Legion's Karazhan, all of them are classic dungeons: Maraudon, Stratholme, Blackrock Spire, Blackrock Depths etc.) or multiple separate dungeons sharing the same location (these were mostly in BC, and smaller versions in WotLK: Auchindoun, Hellfire Citadel, Tempest Keep 5 man, Icecrown Citadel 5 man etc.).

• Legion's Karazhan would as a blueprint for them regarding length, mob density and strength, boss difficulty etc.
• The mini raid would consist of multiple adjacent dungeons (which can be beaten individually), however while having to raid all dungeons.
• This type wouldn't be a classic mythic+ dungeon, i.e. no m+ loot system or timed challenge - more an exceptionally long and challenging dungeon; however, these multi-wing instances would need several difficulty levels to avoid them growing stale quickly
• In order to make these dungeons more rewarding, they would get bonus bosses or final bosses which aren't accessible to other means than by running the mini raid (think of Nightbane). 

Recycle old instances as Mythic instances
WoW has a wealth of decent older instances; but up until the introduction of Mythic+, 5man instances simply were never really that interesting as endgame content, which also made recycling instances not that appealing (and the way timewalking was handled certainly wasn't that great either). Now that that has changed, retuning them to be actual new content would be an interesting addition.

Raids as Mythic instances
Raids, as one of the central PvE features of WoW, was generally reserved for those players who were willing to submit to a raid schedule. With Mythic+ as an endgame option, it would be possible to also offer a retuned version of a raid which is also accessible to smaller groups but on the other hand also is challenging and not the same lackluster experience LFR is (don't say it won't work - it did with the troll instances and Karazhan). I am not suggesting handing out the same loot as actual raiding does (the Mythic+ rules for loot should do the job just fine), just something comparable to the full experience including an actual challenge for people who don't want to raid.

Mythic+ difficulty adjustment

The current state of (and the biggest problem with) M+ difficulty is that several insufficiently balanced instances were pitted against one another, while the HP/daMage increase for each + as well as the affixes were indiscriminately slapped on them with little regard of how the ultimate result turned out. Here are a few ideas on how to balance M+ dungeons more thoroughly:

• Baseline difficulty should be roughly equal: it hardly matters for a seasoned player if a heroic instance is ridiculously easy or just reasonable. However, while this wasn't really a problem back then when Heroics were the top of the totem pole, this becomes a serious issue with potentially unlimited difficulty: because the difference between "ridiculously easy" and "reasonable" becomes one between "keystone level 15 possible" and "automatic failure at keystone level 10". The bottom line is: the difficulty level of the baseline mythic instances should be roughly within the same ballpark.
• Instances that are later patch additions should also be designed with respect for the difficulty classes for M+. This means that for example the normal M+2 iteration of Karazhan would have been considerably easier than the standard mythic version we got in the game (which was more on par with other +10 instances at the time it was introduced).
• Rework the affix rotation: instead of indiscriminately adding changing affixes to all dungeons every week, the whole M+ system requires an overhaul. This means that in the first place, the difficulty increase would have to be tailor-made for every instance to avoid ridiculously easy combinations on the one hand and pointlessly difficult combinations on the other. This is a bit of work, but considering the fact that M+ is rather popular overall, this should be worth it.
•  Mob type skills: every mob type starts out with baseline abilities they have and get additional active and passive abilities the higher the keystone gets. An alternative to this would be that the weekly rotation of abilities isn’t applied to the entire dungeons, but on the mob/mob group level: the biggest and singlemost important difference to the current affix system would be that this rotation would be defined on a mob type-basis and not slapped summarily on all mobs, so really nasty and plain and simply unfair combinations could be excluded in the first place.
• Group powers: instead of (or in addition to) mob type skills, all mobs of a separate pull group get additional abilities (in this case, the classic affixes would be a good fit) which are balanced around the group composition. For example groups with 20 mobs won't spawn explosive orbs, while groups with mini bosses won't enrage etc.
• Mob composition: instead of teeming as a separate affix, the entire instance becomes more crowded as a rule with rising keystone levels.
• Boss tuning: bosses should also be separately tuned, including  oneshot mechanics and soft enraging, to avoid widening difficulty gaps - if instances have those (and some do), they should roughly be fatal at the same keystone level for people with the same ilvl.

 

An illustration of how various of these suggested changes might look like. No, this is not supposed to be a balanced map.