Something's not right with the whole Earth Giants -> Gronn -> Ogres -> Orcs things.
How can the Orcs fear the Gronn and to a lesser extent the Ogres? But they can annihilate the creatures bigger than Gronn with ease?
I mean, the story of the giant corpses that were used to build the Temple of the Damned? It doesn't add up.
Having the Night Elves come from Dark Trolls that lived near the Well of Eternity makes at least some sense. They were changed due to the magical power.
And Humans coming from mutated Vrykul that were affected with the Curse of Flesh? Well, that makes some sense too.
What do these have in common? They were changed by magic.
But having Orcs be descended from Ogres? yeah right. It does not add up. There is no major magical force at work here.
Gronn were killing Black Dragons like it was nothing. The Orcs feared them. Yet the Orcs also killed beings bigger than them with ease. How?
Maybe the people that said Garrosh looked like an Ogre are to blame, I guess Blizzard thought it was pretty nifty.