In regards to both of you, yes the item will be BIS until AB is released.
But you also need to consider that the boots require you to be revered with Arathi basin if I remember correctly.
This means that even with phase3 released, it will take significant time to purchase the item itself.
So Caverndeep are the dream for any twink warrior/Ret paladin for a very long time, and will always be relevant for newly made twinks.