Yes, I know this is a little late
The point is there any weapon you feel should've been an artifact instead of what we actually got
For me:
Arms Warrior: Axe of Cenarius; I honestly feel that this weapon could've been used, sure Nature isn't really a theme Warriors have, but such a legendary weapon would've been a thrill to wield
Holy Priest: Fearbreaker; this weapon has been implied to have had healing powers when it was first given to Anduin, and it would've been a nice alternative to another staff
Enhancement Shaman: Sulfuras; This weapon is far cooler to me than the Doomhammer, and also would've allowed Thrall to keep the weapon that has been synonymous to him for decades, and honestly I think having Enhancement be a 2 hander wielder instead of a duel wielder