I think, at the minimum, this gives Blizzard the hook to do it while still allowing them to pivot. I think though that adding something like an entirely new spec is far too big of a change to just spring on us. This is a type of change that is much more fitting as an expansion feature.
And honestly I can see the next expansion opening up classes/specs more. Blizzard is already just tossing classes to all races willy nilly and their biggest competitor and number 1 MMO, FFXIV, has supported a character being all classes and professions since their vanilla. I can see a world where we get “dual classes” or even “sub specs” where players can adopt the basic spellbook of any other class if not straight up class changing.
We also lack a true “magic tank” though I think it makes 1000000000% more sense for it to be mages and a spin off or advancement of arcane. I mean we literally already have a mage tank template in Nighthold. What I HIGHLY doubt a mage and/or evoker tank being though is a RANGE tank. Mechanically, that just doesn’t work. I can see a world where you cast spells that aren’t interruptible or pushed back or have hybrid melee and spell-like abilities, but never in a world where you aren’t in melee combat.
Personally, I think we do not need another tank and DEFINITELY not more melee in general. I wish Blizzard would stop contributing to world of meleecraft and let casters have some actual love and time to shine.