World of Warcraft one hit kill

As I have done this before It has happened to me (my 80 mage, and my 20 mage, all my characters, from cloth to mail)
You make a rogue, and if you have boa you can handle such power at level 10, but once your 16-19 you can overpower warriors.
Go subtly, use shadowstep to increase ambush (must be in stealth) then attack. Focus all talents on ambush. Note: If you ambush a warrior or a warlock with high health you should be careful if you fail to 1-hit them you will want to be able to kill them so skill is needed.
But yeah its one way....
Pyroblast on the mage can 1-hit lower levels, for example at level 15 you can cause up to 450 fire damage