They could make him a SMN pet in that they can call him but maybe not use him. I think most SMN are used to XI and him being your first avatar and first to keep out with no mp cost with the right gear. I agree that he should still be usable after ACN is done. I mean no one plays classes and after you unlock the job carbuncle is tossed to the curb and to me he is kind of the main reason I also went to SMN in XIV.