Subraces....

[Angeredsoul]

Let's bring some diversity to the game.

Mag'har orcs
Broken Draeni
High elves
Dwarf factions
Troll factions

Just to name a few, I mean if you could play as Amani troll like zuljin I'd be on that faction change pages so fast.

[Varvara Spiros Gelashvili]

Mecha or leaper gnomes would be cool.

[Muxtar]

Argent Dawn/Crusade
Grimtotem tauren
Iron dwarves
Scourge undead (under Fordragon command I suppose)
Vrykul
Cenarion Circle/Expedition
Sporeggar
Dragonmaw orc clan (TBC or Cata one, w/e)

[McNeil]

Orc - brown (Mag'har), red (fel orc), Dragonmaw
Dwarf - Dark Iron, Wildhammer, Iron Dwarf
Tauren - Grimtotem, Taunka, Yaungol
Troll - Forest, Jungle, Frost, Sand, Dark
Blood elves - Fel Elf, Darkfallen, High Elf
Goblin - Gilblin, Hobgoblin
Night elf - Fire Elf (from Firelands), Highborne
Draenei - Broken

Just to name a few.