this has nothing to do with under- or overpowered, only with how easy it is to use 2014 subclasses in 2024. So far that looks pretty straightforward, and I have no reason to believe that it will become less soConsidering WotC's track record with over- and under-powered archetypes and spells, and with half-baked rules, it makes a lot more sense to accept there could be problems right now then just assume everything is going to be perfect.
I am not saying there will be no issues whatsoever, but your concern seems way overblown.
So far you have nothing but a vague feeling, you will need more to convince me, so I suggest we revisit that once the 2024 books are out. Until then you have nothing, as you yourself said.
We won't know until the books come out.
I am not sure why this is enough to convince you, it sure isn’t enough to convince me.