I had an idea that maybe depending on your race/class combination you could be granted an exclusive title granted from a questline or whatever, it would be fun for customisation and would feel rewarding having it there, also it would cover some of the clamoring for old RTS hero classes that have already been covered
Human
Warrior:Knight
Priest:Archbishop
Paladin:Lightbringer (since paladin was already a sort of hero title it was hard to think of one, i thought this would be an appropriate cool sounding title and a tribute to uther)
Hunter: Watchman
Warlock: Cultist
Mage: Archmage
Monk: The Noble Lion/Lioness
Dwarf
Warrior: Mountain King
Priest: Cleric
Paladin: Crusader
Hunter: Rifleman (THE PINNACLE OF DWARF HUNTER-DOM)
Warlock: Cabalist
Mage: Sorcerer/Sorceress
Rogue: Brigand
Monk: of the Thousand Facial Hairs
Shaman: Stormhammer
Gnome
Warrior: Steam Warrior
Priest: Medic
Mage: Techno-Mage
Warlock: Technomancer
Rogue: Ace
Monk: Friend of the Small
Night Elf
Warrior: Sentinel
Hunter: Archer/Huntress
Rogue: Warden
Mage: Highborne
Druid: Archdruid
Monk: of the Serene Forest
Priest: Priest of the Moon/Priestess of the Moon (very unsure about this tbh)
Draenei
Warrior: Exarch
Priest: Anchorite
Shaman: Elder Sage
Hunter: Tracker
Mage: Harbinger
Monk: of the Countless Stars
Worgen:
Warrior: Alpha
Priest: Darksoul
Mage: Wizard (because of the whole ye olde Britain thing it's got going on )
Warlock: Shadow Weaver
Druid: Moonwalker
Rogue: Dark Runner
Hunter: Stalker
Orc:
Warrior: Blademaster
Mage: Pyremaster
Warlock: Necrolyte
Shaman: Far Seer
Rogue: Spymaster
Hunter: Beastmaster
Monk: The Iron Fist
Troll
Warrior: Berserker
Mage: Hexer
Shaman: , The Fire-Eater
Warlock: Doomsayer
Priest: Witch Doctor
Hunter: Shadow Hunter/Headhunter (dunno about this one)
Rogue: Assassin
Monk: Bane of Shadowy Voodoo
Druid: Subversive
Tauren:
Warrior: Primalist/Chieftain (unsure about this as well)
Druid: Nature Guardian
Shaman: Spirit Walker
Paladin: Sunwalker
Priest: Sun Seer
Monk: Runemaster
Undead:
Warrior: Deathguard
Hunter: Dark Ranger
Rogue: Deathstalker
Mage: Conjuror
Warlock: Acolyte
Priest: Disciple
Monk: of the Relentless Soul
Blood Elf:
Warrior: Spellbreaker/Guardian
Hunter: Ranger
Rogue: Bandit Lord
Mage: Magister/Magistrix
Warlock: Blood Mage
Paladin: Blood Knight
Priest: Dawn Priest
Monk: of the Enduring Hardship
Goblin:
Warrior: Bruiser
Rogue: Saboteur
Mage: Moolah Magician (i loved this one too much to place any other)
Warlock: Netherologist
Shaman: Geomancer
Priest: Soothsayer
Hunter: Sharpshooter
Pandaren:
Warrior: Champion of the Fatal Strike
Shaman: Master of the Four Elements
Priest: Safeguard of the Eternal Battle
Mage: Maestro of the Many Magics
Monk: Sensei
Death Knight titles (with thanks to Teebone):
Human: Death Bringer ____
Gnome: ___ of Rusted Gears
Draenei: ___ the Fallen
Dwarf: Dark Mountaineer ___
Night Elf: Moonfell ___
Worgen: Rotting Fang ____
Orc: Revenant ____
Undead Reaper ____
Tauren: ____ of the Dusk
Troll: Blood Lord ___
Blood Elf: Plague Knight ____
Goblin: ____ the Bankrupt
no gameplay changed side from the inevitable talent you'd get at that level anyway, nobody left out, just one questline needed and 2kb worth of variable text data
I can tell im gonna get that classic mmo-champion "NO SHUT UP, YOUR IDEAS ARE STUPID, SHUT UP PLEASE OH MY GOD PLEASE SHUT UP PEASANT" treatment, its just some fun and if something like this gets implemented, it wouldnt harm anybody! it'd just be badass to be able to play
VINDICATOR SPACEHOOF
or
GNOMERCY, FRIEND OF THE SMALL
or
PYREMASTER ZUGZUG
besides, how many "saviours of azeroth" can we have? These titles might not be much of an incentive to experiment with race/class combos, but they would give a nice little feeling
EDIT:
Also some people are asking for spec-specific titles,
i.e Chaos Reaver for Destro Warlocks
Druid of the Claw for Feral Druids