You could make macros, for example if your a mage make a frost nova, teleport macro. Now have your speech recognition use that macro when you shout "ambushed". So using a combination of mouse, keyboard and voice you will have the fatest reflexes.

say "(petname) Attack"
Your character selects target in front of you, cast Hunter's Mark and sends your pet to attack.

As your walking is over corpses in pve, say "loot" and your character picks up nearest loot.

When your running the flag in PvP, (as a hunter) say "cripple" and your hunter uses that cripple sword swipe move on the target in front of you and then uses his speed boost stance right after it.

These are just some examples I can think of for quick reflex actions you can use in WoW.