Considering that Chen's presence in TFT has been lore since Vanilla (and frankly before that point since the WC RPG books were canon when they were published), I don't see how you can make that argument.
Incorrect. There will always be some variations from hero to playable class due to spec requirements.If your argument is "this character is the only option", that means it has to be 100% like him. Because not being "100% like him" means said character is not the only option.
Headcanon.Again, purely by choice, not because lack of ability.
Well yes because Evokers can do everything Alexstraza and other dragons can do (and more). A Mage cannot do everything a Blademaster can do. Not even close in fact.You were the one who equated dragons to evokers because of abilities. That's the same logic.