I think BLZ got real good at balancing PvE overall lately (excluding M+ that still tends to be most momobility tank = goto).
Adding a new class would be something I would have objected to fiercly pre Shadowlands but I'm fine with it now. I dont see a need to give a new class 3 (I guess 4 specs wont ever come back) specs though. Every new spec just adds to the really really hard task of balancing.
Giving mr Dragling two ranged dps specs would be a bit tricky I think, hard to distinguish them from mage/warlock but I'm sure BLZ thought of giving it 2 healer specs but ruled that out for the same reason.
It will be interesting to see what comes as more news comes and the elephant in the room, will BLZ say "It's a hero class but we wont do the same mistake as with DK's *cough*"