Is every single WoW character canon?

It was comfy. It rewarded you for knowing what you were doing and in general variety in party compositions.
This. Also the lore went to shit during Cataclysm. They no longer could use actually beloved characters from w3 and had to make up some china-tier villain.

Only if you're an absolute shitter. Even different ranks of spells had their strategic uses back in the day.

>Blood elves
>Undead elves
>Void elves
>Kael'thas elves
Somehow an almost extinct race managed to create all of these huge factions

No, only some, I would guess that one of each class/spec/race combo is cannon, based on how the books say "champions" and "heroes" and how the books treat the efforts of the players.

Yes. You play the role of a "Champion" of your faction, the Argent Dawn, etc. Your character's name is not canon, but your feats are.

Yes but that's because your character fills that role. You don't know the other champions personally, they are just people. You are simply living through the champions eyes.

Imagine defending WoW's pruning.

remember when shamans could tank

it's lame though, a featureless blob "the champion" doing things

remember when classes were actually different from each other?

did you not pvp? if all you used was frostbolt i'd be pounding your pve carebear ass all night