Hearthstone is irrelevant regarding WoW’s character portrayal. You are using another game as the basis of your argument but the let’s see actual in-game portrayal:
Death Knight: Darion Morgraine… Which race does he belong to, again?
Demon Hunter: Illidan Stormrage (but ooops!! Elf-only class)
Warrior: we had MU Grommash dying to average Pit Lord in WC3, Garrosh getting beaten after being empowered by Old God juice and Varian destroying a Fel Reaver solo before dying heroically… Guess which one of these three seems more powerful by his own means?
Rogue: so far we have Human Mathias Shaw stealing the spy screentime for rogues of all races, which yes, makes him the most relevant character (I don’t want to argue about power cause so far and with the exception of Lorash, most rogues hardly get enough focus on the story to properly evaluate their power and skills. You could say Valeera, but let’s be honest, when one compares her actual fail portrayal in the comics with the other rogues she comes as VERY unskilled).
Hunter: this is a hard one. MM types are a discussion between the older Windrunner nutjobs and Shandris, while BM is Rexxar. I’ll concede this one.
Mage: Jaina, Khadgar, Medivh, Aegwyn… Nuff said.
Warlock: before Legion resurrected Gul’dan as raid fodder, the most prominent warlock was Karenthrad (fangirled even by his Forsaken lock partner in the old quest chain for cosmetic green fire)
Priest: God King Blanduin Wrynn, nuff said.
Monk: Chem is the most relevant, I’ll concede him too.
Paladin: Turalyon, Uther.
So far… Seems like in most cases in which humans can roll the classes, they will get the perks of being either the most prominent and/or the most powerful. Out of the 9 classes they can appear as, they have borderline Mary Sues in 7 of them… Totally against the trope we were talking about.
And your posting character is irrelevant, you are still the one trying to dismiss the gross pro-human agenda this game has in regards to character portrayal.