Wonderment,
Paul says the Father is excluded in 1 Corinthians 15:27 because of the statement in 15:28. Once all things are reconciled/put under the reign of the Son, the meditorial mode called the Son will subject to God that God may be all in all. Also God made the Son heir of all things and gave him All authority. He must be worshipped as Jesus Christ the highest authority in the universe. He is not making an argument that All things have excptions or that the Son is a creature. The Son is the Word made flesh, a specific mode of God revealed to reconcile / finish creation.