Yes, but if it happened I'd probably want to see some of the current specs re-worked a bit. My idea would probably be something like this:
Death Knight: All current specs retained as they are, new spec added using Intellect plate, Caster DPS using the runeblade as a ranged focus instead of a melee weapon. I'm picturing something like a crackling jade lightning or the Lich King's attack during transitions for a main attack.
Druid: Already has 4 specs.
Hunter: New spec added as a tanking spec, using the pet to supplement defensively. (Pet attacks would form the basis for active mitigation). Could fight with bow or with spear/polearm/dual wield, I could see it working either way. Would prefer melee, but see argument for ranged for sake of consistency across specs.
Mage: All current specs retained. New spec: Healing spec, with focus on time effects (healing spells that heal a baseline amount, plus a percentage of recently taken damage.
Monk: All current specs retained, new caster DPS spec added, uses new Stance of the <Adjective> Crane, thematically based off of Chi-Ji.
Paladin: All current specs retained, save that holy paladin absorbs are reworked to function similarly to disc priest absorbs (see below). Caster DPS spec added using Intellect plate.
Priest: Holy spec loses dps boosting capabilities. New caster DPS spec added focusing on holy damage, unable to use shadow spells. Discipline shields re-worked to only absorb a percentage of incoming damage, but heals are strengthened to strike a balance between prevention and healing.
Rogue: Assassination and Subtlety retained as are, save that Subtlety is slightly reworked to ensure non-dagger weapons are always at least as good as dagger weapons. Combat re-worked to be a tanking spec. New DPS spec added to be ranged combat, with less capability for control, using ranged weapons.
Shaman: Current specs retained. New spec added as tanking spec. Pretty straightforward functionality here.... probably implement a new shield of some sort (Rock Shield) to work as one form of active mitigation, totems would probably serve as major defensives.
Warlock: Demon Hunter spec. I don't really see Demon Hunter working as a full class, but a melee-focused Warlock using demonic power to protect and empower could work relatively easy.
Warrior: I love the idea of a support spec, but without reworking all raids and dungeons to be tuned around the idea of using a spec role, I don't see it working. Honestly, this is the hardest for me, because I don't see any warrior concept that permits healing, they've got the DPS covered already (2H, DW both 1H and 2H) and I don't see room for a plate range physical dps. Part of me would love to see a second tanking spec that's more offensive, but if it works well that would pretty well eliminate the need for the current prot spec. For lack of a better idea, I'd probably split Fury into two specs, one for Titan's Grip and one for Single-Minded Fury, and add a bit more diversity to the two to make them feel more unique... but I'm not sure I like that solution.