I’m far from the first person to mention it, I just wanted to pitch my ideas out there.
I’m sure Blizzard doesn’t want to balance even more classes in the game, and there’s plenty of themes left unexplored because we kinda have the classes occupying all the “big niches” already. i.e. Every holy warrior is a Paladin, every elementalist is a Shaman, etc.
But what if a class were mechanically identical to another but had new visual effects pertaining to its theme? It would function akin to glyphs but spanning the whole class, and (depending on the skin in question) be locked to a particular race. This could also allow for previously unfeasible class/race combinations to be available specifically under these new class skins. (i.e. You can’t be a Night Elf Paladin, but you can be a Night Elf War-Priest, and you can’t be a Mechagnome Shaman but you can be a Mechagnome Tinker.)
Some examples.
Warrior: Spellblade
Spellblade
Potential races: Human, Void Elf, Draenei/Lightforged Draenei, Undead, Blood Elf, Nightborne
Rather than relying on pure brute force, the Spellblade is a martial spellcaster who devotes their arcane prowess to honing their deadliness on the battlefield.
Unique Cosmetic: Alternate combat animations. (i.e. More elegant movements, less brute force smashing and crashing.)
Example Abilities:
- Charge replaced with Phase Dash. Become ethereal to phase near-instantly to your enemy, colliding with them when you become corporeal on arrival. (i.e. the way Nightborne guards charge in Suramar.)
- Berserker Rage replaced with Absolute Focus.
- Heroic Leap replaced with Phase Leap. Vanish and then reappear at the target location, displacing enemies with concussive force and dealing X physical damage.
- Battle Shout replaced with Arcane Intuition. Share your preternatural knowledge of the flow of battle with your comrades. Cannot stack with Battle Shout.
Hunter: Dark Ranger
Dark Ranger
Potential races: Night Elf, Blood Elf. (+ Void Elf / Nightborne?)
Once disembodied souls, these rangers are brought back to serve again as they did in life, now infusing their abilities with shadowy power and necrotic energies.
Unique Cosmetic: Undead skin. Can use the Death Knight-only skin options but with red eyes instead of blue.
Example Abilities:
- Undead Pet Taming by default.
- Aimed Shot (or Barbed Shot?) replaced by Black Arrow. Wreathe your arrow in dark energy before firing, impacting the target with deadly force.
- Arcane Shot replaced by Shadow Shot.
- Freezing Trap replaced by Paralyzing Rune. Conjure a shadowy rune at the target location, incapacitating the first enemy to step on it for 1 minute.
- Aspect of the Cheetah replaced with Ghostly Stride. Take on a ghostly form and move unimpeded by the weight of your mortal body, shifting gradually back to normal.
Mage: Purifier / Arcanital
Purifier
Potential races: Draenei, Lightforged Draenei
Commanding the power of the Holy Light to cleanse is not always gentle, as proven by the Purifiers, a subset of zealous Anchorites who use their power to purge the wicked.
Unique Cosmetic: Holy abilities. That’s really it. All their spells have golden Light visuals. Fire is golden/white, arcane is gold/white energy, and frost is golden holy crystals.
Example Abilities:
- Summon Water Elemental replaced with Summon Lightspawn.
Arcanital
Potential races: Troll, Zandalari Troll
Though users of arcane secrets, Arcanitals are blessed by the Loa and call upon their wisdom and might rather than relying entirely on the Arcane.
Unique Cosmetic: Loa abilities. Some abilities are tinged with golden/holy energies while others are teal/spiritual.
Example Abilities:
- Dragon’s Breath replaced with Rezan’s Roar. Conjure an effigy of a furious devilsaur to blast your foes with its rage.
- Summon Water Elemental replaced with Summon Spirit.
Rogue: Revenant
Revenant
Potential races: Any?
Like the Dark Rangers, the Revenant is a spirit, tainted by their own hatred and thirst for justice, returned from the dead to possess its former body in an unceasing hunt for vengeance.
Unique Cosmetic: Undead skin. Can use the Death Knight-only skin options but with ghostly pale/teal eyes instead of blue.
Example Abilities:
- Pistol Shot replaced with Necrotic Touch. Blast your target with a quick burst of necrotic energy, dealing damage and slowing their movement.
- Between the Eyes replaced with Toll the Bell. Summon a ghostly bell that shatters against your target, increasing your critical strike chance against the target by 20%. Critical strikes with this ability deal four times normal damage. (Deals X damage and stuns for Y seconds)
Priest: Anchorite / Voidbound / Priest(ess) of Elune / Loa Priest / Tidesage
Anchorite
Potential races: Draenei, Lightforged Draenei
Unique Cosmetic: Entirely holy-themed abilities.
Voidbound
Potential races: Void Elf, Undead
Unique Cosmetic: Entirely shadowy abilities.
Priest(ess) of Elune
Potential races: Night Elf, Nightborne
Unique Cosmetic: Holy/Discipline (i.e. gold) abilities replaced with silvery white abilities. Black/purple shadowy abilities replaced with midnight, blue-black abilities.
Example Abilities:
- Shadowfiend replaced with Spirit of Vengeance, a spectral warden that attacks the target.
Loa Priest
Potential races: Troll, Zandalari Troll
Unique Cosmetic: Voodoo/Loa-themed abilities, i.e. pterrodax/bat wings instead of feathery golden ones, teal spiritual energy or green nature energy.
Example Abilities:
- Shadowfiend replaced with Servant of Bwonsamdi, a ghostly tribal warrior that attacks the target.
Tidesage
Potential races: Kul Tiran, Undead
Unique Cosmetic: Watery abilities, akin to Restoration Shaman.
Example Abilities:
- Shadowfiend replaced with Tidesurger, a wild water elemental.
Warlock: Necromancer
Necromancer
Potential races: Any Warlock-available race (+ Mag’har?)
Summoners of the living dead and user of dark magic. These don’t need an explanation.
Unique Cosmetic: Undead skin. Can use the Death Knight-only skin options. All demons are replaced with Undead equivalents. Fiery abilities visually replaced with Frost, Fel abilities visually replaced with Necrotic.
Example Abilities:
- Summon Imp replaced with Summon Skeletal Mage.
- Summon Voidwalker replaced with Summon Abomination.
- Summon Succubus replaced with Summon Banshee.
Shaman: Tinker
Tinker
Potential races: Dwarf, Dark Iron, Gnome, Mechagnome, Draenei, Lightforged Draenei, Undead, Goblin, Blood Elf, Nightborne, Orc, Mag’har
Utilizing high-tech gadgetry and tools, full-time Tinkers are a step above the casual Engineer profession.
Unique Cosmetic: Each Tinker race has unique visuals for turrets/machines. i.e. Akin to unique shaman totems for each race. Orc/Mag’har have Iron Horde style machines, Draenei/Belves have more Magic-Tech style stuff, etc.
Example Abilities:
- Windfury Totem replaced with Acceleration Matrix. Plant a device at your feet, causing all allies within X yards to have a Y% chance of gaining a bonus auto-attack.
- Earthbind Totem replaced with Deceleration Matrix. Plant a device at the target location, causing enemies within X yards to be have their movement speed reduced by Y%.
- Fire Elemental replaced with Overloaded Construct. Activate a golem with an overloaded power core, dealing fire damage and using various abilities.
And that’s about where I run out of steam on coming up with these. Additionally, Monk could have Brawler that uses more standard rough boxing/fisticuffs over martial artistry.
Edit: Taking another crack at adding more ideas.
Paladin: War-Priest of Elune, Tideguard, Sunwalker, Prelate
War-Priest of Elune
Potential races: Night Elves
Infused with the power of the aspects of Mother Moon and the Night Warrior, these soldiers of the Kaldorei can call upon both the Goddess’ healing light or her terrible wrath.
Unique Cosmetic: All abilities themed towards moonlight/eclipses/etc. Healing/shields would be silvery white moonlight, while attacks would be infused with starry black energy a la the Night Warrior.
Example Abilities:
- Crusader Strike replaced with Crescent Strike.
- Consecration replaced with Rays of Moonlight. Cast the light of Elune down upon the area around you, causing holy damage over 12 seconds to enemies who enter the area.
- Templar’s Verdict replaced with Midnight Verdict.
Tideguard
Potential races: Kul Tiran (Undead?)
Calling upon the power of the Tidemother to protect their allies and crash against their foes, the Tideguard are the martial branch of the Stormsong Tidesages.
Unique Cosmetic: All abilities themed towards ocean/water/etc, akin to Tidesages.
Example Abilities:
- Hammer of Justice replaced with Stunning Bolt. Call down a sudden bolt of lightning to stun the target for X seconds.
- Consecration replaced with Shocking Waters. Conjure electrified waves to churn through the area around you, causing holy damage over 12 seconds to enemies who enter the area.
- Divine Steed replaced with Tidesurge. Summon a wave of surging water to carry you swiftly, increasing movement speed by 100% for 3 seconds.
Prelate
Potential races: Zandalari
Acting as the vanguard to the Zandalari Empire, the prelates faced a crisis when the great Loa of Kings was slain. Now, like the Zandalari Kings and Queens, they call upon the blessings of all Loa to serve their people.
Unique Cosmetic: Abilities infused with a more nature/spiritual appearance in addition to having Loa-themed attacks.
Example Abilities:
- Avenging Wrath replaced with Rezan’s Wrath. Though the great Devilsaur Loa is gone, you still call upon an echo of his unending might to infuse you with power, enlarging your size and summoning a glowing visage of a devilsaur around you.
- Divine Steed replaced with Packstrider. Take upon the form of a golden ravasaur as you lunge swiftly through the battlefield, granting 100% increased movement speed for 3 seconds.
- Wake of Ashes replaced with Tiger Slash. Lash out with Kimbul’s claws, shredding foes in front of you and infusing you with his holy power.
- Divine Shield replaced with Torcali’s Guard.
- Blessing of Freedom replaced with Blessing of Pa’ku.