But I never said Arthas would *be* a Bard. I would point that out as an example of how the aesthetic *still fits WoW* as a full package game that IS full of shits-and-giggles easter eggs and fun stuff, alongside your hardcore high-fantasy tropes. Warcraft is absolutely a mixed bag, and you can't just cherry pick the fantasy as being what WoW's aesthetic is all about and trying to dismiss all the other non-fantasy stuff that literally permeates the game.
At the base level, a Bard class would play as you normally expect out of an RPG Bard class. Yet Blizzard can always keep the design open to enough to throw in some easter egg or homage abilities/talents, just for the sake of fan service and crowd pleasing. We have this already happening in existing classes, and every class has some level of absurdity attached to them. Mages had a Sheep Stick Artifact skin. Hunters could tame some really strange pets like a Robot Chicken or Mechanical Squirrel. Druids could turn into a Flaming Cat, where it absolutely makes no sense in the lore for them to have that ability.
Fun stuff permeates classes. Why are you so upset about Heavy Metal?