i believe it would work if he had a Philospher's stone. remember the stone has the power of many human souls. Ed stated that every human is in fact their own philospher's stone they simply have the power of one soul instead of millions. Ed gave up his gate as a payment to get Al back. a philospher's stone gives the illusion of alchemy without equivalent exchange. because it has the power of that many souls so using the stone would indeed get his back or atleast give him a brand new one. if they wanted to make another series they would have to give a reason for Ed to get his alchemy back. maybe Al getting kidnapped or winry getting kidnapped or one of his children getting kidnapped etc etc.

I believe it would work if he had a Philospher's Stone. Remember the stone has the power of many human souls. Ed stated that every human is in fact their own Philospher's Stone, except each person simply has the power of one soul instead of millions. Ed gave up his gate as a payment to get Al back. A Philospher's Stone gives the illusion of alchemy without equivalent exchange, because it has the power of many souls, so using the stone would indeed get his back, or at least give him a brand new one.