PVE Bellow Level Cap.
1. levels 10-50 are for leveling.
Any zone ingame would be possible to level up in. Would take completing any 3 zone to level from 1 to 50.
Any 100% new player would start at level 1 for the first time and have a basic tutorial to learn basic rotation, UI and movement from level 1 to level 10.
It would take no longer than 30 minutes to complete level 1 - 10 tutorial.
For any returning player new characters would have an option to start at level 10.
levels 1-50 will never get level or stat squished again.
2. Unified currency for upgrading gear. Justice Points.
You Still get new item drops like you always did, yet you have option to upgrade any item or to destroy item to gain currency it in order to upgrade any item in your possession. It would only be a matter of simply setting reasonable ilevel caps on upgrades for each character level.
3. Any dungeon / raid (or any other legacy instanced content) that is not current content is to be scaled from 10 to 50 and serve as leveling option via lfd tool or by simply by walking in. Once new expansion releases the replaced one will automatically switch in to legacy content and follow the pattern of any other older expansion in 10-50 leveling bracket.
4. Add Timewalking hub area with easy access to any level. Theme-based subareas with vendors to represent each expansion that would always be active. On top of usual vendors there would be material and rare cosmetic and pattern boe drops from related expansions that would be sold for Timewalking badges.
Could also house area for different questing npc in relations to new activities in zones from older expansions.
5. Add a scroll item purchasable for Justice Points that would apply a socket up to 3 times per item to any legacy item.
Add an item purchasable for Justice Points that would Upgrade any legacy content item ingame to be level scalable heirloom item from level 1 to level 50.
PVE At and around Max Level Cap.
1. Level 50-60 is for new zones.
Any level 51-60 would get level/item stat squished back to level 50 with the release of next expansion.
That way if you didn't play for few expansions you still will be level 50 ready to go in to latest content with your old gear and effort still having some impact.
2. Level 60 would always be maximum character level that a character would have to "prove its worth" in new continent.
You can still add all the new shiny things to new expansions and experiment with things.
This clear structure will ensure clear understanding of how things are going to be going forward and lapsed player won't feel like there is canyon size gap between them and new expansion.
3. Unified currency for upgrading gear up to heroic raid tier with same Justice Points.
You would still use single currency to upgrade gear. Doing harder content would reward you with more of it.
You still would get new items to drop and ability to upgrade/scrap things without ruining previous effort.
What is left is simply pre set proper costs for 5 raid tiers worth of item upgrades for entire expansion and never having to touch this system again.
Max ilevel gear for any current tier would always come from Mythic raid or similar level of content.
4. Add world quests and daily quests to older zones that would reward timewalking badges.
Rotating number of daily quests 5-10 quests each day that would take player to different older zones.
Potentially this can be a part of Timewalking hub.
5. Add a scroll item purchasable for Justice Points that would apply a socket up to 3 times per item to any current expansion endgame item.
While you at it maybe even add new gems with unique spells that are not just passive stat boost.
PvP. Progression, Leveling & Endgame.
1. Set GCD in pvp to 3 seconds.
2. Limit (with the player aura) the amount of maximum damage & healing a spell can do in pvp. Not greater than 10% of targets hp.
3. Cap moving speed in pvp. Not Greater Than: Player unmounted = 125%. Player mounted = 160%.
4. Set up two pvp brakets. Leveling scaling level 10-59. Endgame level 60.
Any level 10 would have stamina and primary stats of a level 59 in battleground. Extra levels and gear would increase health, damage and secondary stats.
To a reasonable point.
5. Create PvP specific UI journal tab with daily, weekly, season rewards. Similar to Traveler's Log.
Clear information on all pvp progression, activity and possible rewards. Does not have to be updated every month. But cmon, atleast once per season...
While the 3 second global cooldown (gcd) is not essential - it is a good start. The goal is to slow down action count of gameplay, have less informational/meaningless action bloat, make player actions more thoughtful and to have a mistake cost.
While secondary stats can be a good way for overall character progression and haste could lower gcd, the goal is to have 2 player actions within 5 seconds.
Granted all 5 of this steps would be implemented item levels in pvp would not need to be any different to pve progression.
The only thing left would be to ensure reasonable difference in stat distribution between item levels for level 10 - 59.
Core spells for each class are already available at level 10.
For Max level instanced pvp gear would be scaled to normal raid item level as starting point.
Justice Points can replace honor points or you can have both. Granted there is a similar speed of acquisition vs time spent doing activities.
The gear upgrades in pvp would cap out at heroic raid item level for each season/tier.
Overall Class balance.
It is my humble opinion that they fear actual class Balance.
For some bizarre reason they associate it with stagnation.
There is no logical reason why you would ever need to buff something by 25% or nerf something by 50%.
Unless you are Regarded in the first place.
While it is my humble opinion that the type of gear progression suggested (granted stat distribution is accurate) will bring alot of class balance in pve and pvp, the actual way to solve this would be rethinking the equations that are used by spells in background.
5-7 modifiers for each spell is mental.
Clearly it does not bring class balance.
Not even after all this years.
Atleast in current hands it does not.
Simple/fast solution would be blanket class or spec hidden aura buff in instance pve content that would increase output damage/heal to desired level.
The main thing is that one needs to commit to it. Not to abandon it or do their best to undermine it the very next patch to prove a point.
---------------------
Scenario 1 you leave current formulas for all the different spells like they are now. Random mess.
Instead of running around every single patch from one spell to another across increasing number of specs/spells and all the modifiers within trying to buff or nerf it - apply single global aura to each spec to boost output based of how far behind the spec is from others and desired number.
As i have stated it is a fast solution and not ideal one.
We are still left with all the mess in the back and you will have to commit to update auras it as time goes on.
Scenario 2 you categorize each spell from all the classes based of what they do and how they intended to work.
Instant single target damage spell, Castable single target damage spell.
Instant aoe damage spell, Castable aoe damage spell.
Instant dot damage spell, Castable dot damage spell.
Once you categorized all that you apply general formula that will control output damage for specific group.
Far easier to manage it this way and on the outside it will look mostly the same.
Can go even further and ensure things like spell cost, cooldown, cast time, duration is somewhat similar (since we established we don't want 100% accuracy).
On top of that you ensure that stat distribution from gear progression is reasonable and that would be far easier to do if you only ever going to have endgame progression from level 50 to level 60. You not going to have 1k+ main stats on single peace of gear which is absurd anyway.