I couldn’t let go of the idea of an Evoker tank spec, so I wrote it all out to get it out of my head. I am not a game developer, but I’ve been a tank a long time, and a caster almost as often. I feel like some powerful and interesting niches are still missing in WoW. Namely, the battle-mage and caster tank are holes in the tank options in-game. And I think my project does a pretty good job of fleshing that out.
The idea of the Chromatic Evoker is based on the fact that the ultimate army will always require resilient infantry. Neltharion, as the Earth Warder would have felt the duty of protecting Azeroth -and its life forms - keenly before his madness, and would have made sure his creations could do this service. Also, various times throughout his time before his madness, he endorsed an obvious theme: combining all powers is the most powerful option. From defeating Galakrond to forging the Demon Soul, he knew - and convinced others - that working together with different skills was the path to victory. He wouldn’t have created the Evokers to largely ignore their affinity for the Earth, nor would he have kept their powers strictly separated when he could have blended them.
The Chromatic Evoker is WoW’s first Intellect Tank - and the first time a Mail-wearer has been able to effectively tank - since Vanilla. No true specialist can do everything, of course. Players will be required to pick from diverse talents to bring the right tools to the fight.
Unique thematic utility for the Chromatic Evoker includes group healing in bursts, unparalleled tanking/kiting range, and the choice of talents to specialize for single or multiple targets. They can also choose talents to support another tank or even feed threat to the other tank.
The Chromatic Evoker has a unique mastery, as well. Mastery: Amalgamation. Casting a spell which is a different color from the previous spell grants stacks of Amalgam. Amalgam: Increase Armor, Parry, Dodge, and Block by (a small amount based on Mastery rating). Max x stacks. Parrying, Dodging, or Blocking an attack consumes 1 stack of Amalgam.
Talents largely leave tuning open for the developers, because we know they can make it work if they wanna. 
You can preview the talent descriptions below. I have tried to emulate the things players are responding well to in feedback threads from other talent trees, but it isn’t perfect or fully fleshed out. This is 100% just design options I thought would be fun to mix up the stale and limited tank meta I’ve spent so many years playing.
Chromatic Evokers weave different dragonflight colors together, so some spells are more than one color, and their biggest cooldown evokes all Aspects they are talented into, blending the flights’ magic to leverage the strengths of the flights.
Spells with a cast time are replaced with chromatic instant abilities, but Empowered abilities still require time to hard-cast, which is offset by Chromatic Burst, which can be talented to be triggered by almost any spell.
Finally, Chromatic Evokers don’t use Essence, instead using a builder-spender for Empower abilities using Chromatic Surge, similar to combo points.
Row 1
Shattered Stone - BLACK - 6 sec cooldown - strikes the target with stone, which then shatters to hit 3 enemies within 10 yards. Grants parry based on targets hit, as the stones continue to assault their targets.
Row 2
Flame Infusion - RED/GREEN - (moderate) second cooldown, 2 charges - strike your foe with the dual nature of dragonflame, dealing damage over time and healing you over time. Replaces Living Flame.
Arcane Aegis - BLUE/BRONZE - (short) sec cooldown, Conjures a shield deal, dealing damage to 3 targets in melee range. For the next 8 seconds, reduce magic damage taken and grant block chance based on your spellpower.
Row 3
Emerald Essence - using a Green spell has a chance to cause a Chromatic Surge, making your next empower spell instantly cast at an empower level equal to your number of stacks of Chromatic Surge.
Guardian of the Deeps - Shattered Stone gains a second charge.
Bronze Essence - casting a bronze spell has a chance to cause a Chromatic Surge, making your next empower spell instantly cast at an empower level equal to your number of stacks of Chromatic Surge.
Arcane Reach - Passive - increases targets hit by Shattered Stone by 1/3. 2 point talent.
Azure Essence - using a Blue spell has a chance to cause a Chromatic Surge, making your next empower spell instantly cast at an empower level equal to your number of stacks of Chromatic Surge.
Row 4
Choice Node:
[Bathed in Flame - Passive - when you consume Essence Burst, you are granted damage reflection.
Rejuvenating Flame - Passive - When you consume Essence Burst, heal yourself.]
Choice Node:
[Seasoned Soldier - When you parry, strike your enemy, ignoring armor.
Infiltrator’s Reprieve - When you dodge an attack, increase healing received.]
Choice Node:
[Arcane Soldier - When you strike more than one target with a single spell, gain a chance to reflect the next spell your Arcane Aegis would reduce.
Borrowed Time - after dealing damage to more than one target, gain increased auto attack speed.]
Row 5:
Predator’s Thirst - gain n% leech.
Chromatic Forge - embrace the healing power of the flights’ flame and magma magics, increasing healing received.
Favor of the Deeps - Black - summon Elemental spirits of Earth to increase your defenses, granting stacks of Amalgamation.
Soldier’s constitution - increased HP.
Eruption - increased range on certain spells.
Row 6:
Quartz Soul - increase your healing done to all targets by (small amount).
Ruby Essence - using a Red spell has a chance to cause a Chromatic Surge, making your next empower spell instantly cast at an empower level equal to your number of stacks of Chromatic Surge.
Choice Node:
[Call of the General - Taunt all enemies near your target.
Delegation - Transfer threat from all enemies to target ally.]
Ebon Essence - using a Black spell has a chance to cause a Chromatic Surge, making your next empower spell instantly cast at an empower level equal to your number of stacks of Chromatic Surge.
Field Soldier’s Expertise - your auto attacks have a n% chance to strike all enemies within range.
Row 7:
Empathic Bond - Green - Evoke the Dreamer’s gift, bonding your life force with another player. While bonded, you each receive n% extra healing, and deal n% less damage. You also both generate increased threat to any target you’re both targeting. Turns into Dreamer’s Grace.
Dreamer’s Grace - for x seconds, you and your bonded ally share your health pool. Your health is increased by (large amount), and you heal for the same amount of health immediately. Long cooldown.
Aspect of the Dream - GREEN- draw on your connection to the dream, for the next x seconds, your Green spells have a reduced cooldown. This ability resets one charge of Flame Infusion. Combines with all Aspect spells you know.
Aspect of Warding - Black - Evoke Neltharion’s natural armor, reducing damage received. Combines with all Aspect spells you know.
Aspect of the Arcane - BLUE - increase all magic damage done by x for a moderate duration. Combines with all Aspect spells you know.
Leyline Incursion - BRONZE - EMPOWER - tap into the eternal ley lines, drawing power from the future and past, coalescing into two waves of sand which deal Arcane damage to all targets between them. Range of cone increases with empower levels.
Row 8:
Burning Empathy - the magic of Alexstrasza and Ysera fills you with restoring flames. When you heal yourself with a spell, duplicate some of the healing onto an ally nearby, favoring your Empathic bond partner.
Choice Node:
[Lifebinder’s Chosen: increase the chance of red spells to trigger Chromatic Surge.
Dreamer’s Preoccupation: increase chance of Green spells to trigger Chromatic Surge.]
Path of Stone - Favor of the Deep’s cooldown is reduced.
Choice Node:
[Timelord’s Obsession - increase the chance of Bronze spells to trigger Essence Burst.
Spellweaver’s Scion - increase the chance of Blue spells to trigger Essence Burst.]
Eruption: when a harmful spell effect is removed from you, you radiate damage for up to (time) seconds based on how much duration was remaining on the debuff.
Row 9:
Choice Node:
[Empowered Prism: casting spells from 4 flights grants you increased health and armor for a short time.
Focused Power - each time you cast a spell that is a repeat of the previous ability, that spell is n% more effective, stacking up to x times. Gaining a stack does not refresh the duration of this buff. Casting a different spell removes the debuff. Casting the same spell again does not interrupt your Mastery so long as the previous unique spell was of a different color.]
Aspect of Flame - Red - draw on your connection to flame and magma, radiating heat and causing nearby targets to burn for x over x seconds. Combines with all Aspect spells you know.
Spiral of Flames - when you reach 4 stacks of Chromatic Surge, your next Flame Breath becomes Flame Spiral, and hits nearby targets, in all directions.
Prophecy: each time you consume Chromatic Surge, you have a chance to foretell the actions of your enemy, reducing the damage done by them for x seconds, based on the number of stacks consumed.
Aspect of Time - BRONZE - Summon a clone of yourself from a potential timeline to deal damage. A small amount of damage you take is redirected to your clone. If you take fatal damage while your clone survives, your clone dies instead, healing you based on the clone’s remaining health. Combines with all Aspect spells you know.
Choice Node:
[Fractal Aegis - Leyline Incursion grants a shield, increasing for targets hit.
Leysurge - Leyline Incursion deals damage a second time at reduced effectiveness when it hits fewer than 5 targets.]
Row 10
Grounded Dreamswell - Black - Empower - Heal yourself for a large amount. The healing is duplicated (split evenly) onto a number of allies based on the empower level.
Chromatic Soul - Consuming Chromatic Surge reduces the cooldown of a random Empower spell.
Timeshattered Earth - Black - stomp on the ground, releasing a wave of temporal energy, shattering the ground in a radius around your. Enemies standing on the fissure deal less damage to you. If you leave the fissure, all enemies nearby are rooted as the fissure collapses.
imgur. com/a/BIqDtpH
I hope you enjoyed this post! Remember, it’s just for fun.