Haven’t read through every single post, so my apologies if these points were already made, but there are a few hero classes that make sense considering these three scenarios:
Tinker - Time is passing by much faster outside of the Shadowlands. Things back on Azeroth might not be anywhere close to the same as we left them, almost of surely won’t be. This goes for technology as well, meaning we could see a more evolved version of Engineering than we see now, with other races having joined in expanding their knowledge, just like when Humans adapted to using magic from High Elves. Gnomes and goblins aren’t the only race who use Engineering, there are several other races that dabble in it, just aren’t as proficient.
Necromancer - With us having spent so much time in the Shadowlands and working along side these covenants, they pass down the knowledge of “manipulating” the dead, powers of the afterlife, or something similar. You know, fantasy stuff. This could work into 3 possible specs: Ranged DPS - something of a true necromancer that summons an undead army (similar to the Mastermind class from City of Villains), Ranged DPS - Using Bone, blood, spirit magic of sorts to attack foes, Healing - Using Kyrian or Night Fae like magic to heal allies.
Dragonsworn - They do seem like they could make it into the game, with Wrathion and the rest of the Aspects doing who knows what right now back on Azeroth, this class could come into play with 3 specs: DPS, Healing, Tank and part of it’s class fantasy is aligning yourself with an Aspect and becoming their Dragonsworn.
These are all far shots by any means, but they do seem the most plausible if you look at the actual hero classes from Warcraft back in the day and the current events taking place, which easy ins for all of the mentioned classes to be looped into the story.
As for Bards, I can’t see these ever making it to the game. This isn’t Monster Hunter. We have enough buffs between the classes that exist as is and since they were an April Fools joke, I doubt they would revisit this.
Thanks for coming to my TED talk.