Some things I came up with in order to get back some of the things we've lost over the years.
- Bigger, less dense zones.
- No iLvl scaling of the outside world.
- "Community servers" without CRZ and sharding.
- Use dailies sometimes instead of world quests.
- Reason to grind mobs, for BOP crafting items for example.
- Remove all dungeon difficulties except mythic and mythic plus.
- Instead of new dungeons, add new dungeon wings later on in the expansion.
- Change raid gear so that normal never offer upgrades over heroic when a new tier comes out, allowing you to continue your progression in heroic.
- Make LFR lag one tier behind.
- Reduce raid power creep. Tier 1: 350/360/370, Tier 2: 360/370/380.
- Offer horizontal progression inside raids if tuning becomes too difficult due to above suggestion.
- Introduce loot lockout on a boss basis. Killing a boss on normal makes you ineligible to loot it on LFR, heroic and mythic.
- Remove mission tables or alter them so we go on the missions ourselves.
- Stop gating off content. Offer replay value or longer completion time instead.
- Make content with flying in mind sometimes instead of holding it off until the end of the expansion.
- Make talents more permanent, making them actual choices you have to make.
- Bring back glyphs.
- Bring back old sockets and gems.
- Bring back old style non generic enchants.
- Make raid gear from current expansion un-transmoggable.
- Make professions relevant again. Allow us to craft gear that isn't immediately invalidated two days later.
- Lessen weapon restrictions, why can't Brewmaster Monks dual wield anymore for example?
- Remove titanforging or cap it at heroic iLvls.
- If titanforging stays, allow us to upgrade our gear through valor points towards the cap.
- Bring back Valor and Conquest gear vendors, offering heroic iLvl loot.
- Bring back tier sets, 8 pieces but keep set bonuses at 2/4.
- Remove uninteresting stats. Versatility and Mastery (for the most part) is just "power", same as int/agi/str.
- Introduce more interesting stats like armor or mp5 that isn't just about damage output in order to make gear less generic.
- Allow gear to have stats you can't use. Bad gear makes good gear better.
- Reduce power creep especially between expansions. Mythic gear could easily last you until the next expansion's dungeons or longer.
- Remove forced personal loot.
- Squish levels. Level up from 1-40 in Eastern Kingdoms or Kalimdor, level up from 40-60 in any expansion.
- Keep cap at 60 forever, give players something else to level up in new expansions. Like a weapon or a neck or your standing with a faction.
- Make levelling last longer.
- Make how classes play more unique. Some homogenization is good though, locking the physical damage debuff to Monk (a class that nobody plays) is bad.
- Take CDs off the GCD again. If the problem is us macroing CDs together, give us less CDs.
- Remove PvP balancing on a ability level. How the hell are you supposed to understand how your abilities work when they change depending on your target?
- Remove melee clutter, allow us to lessen spell effects and pets from other players.
- Give us less gear. Make character progression/advancement take longer and something to work towards.