As we all known, due to the pressure of the inner circle that surrounded him and, in no lesser degree, due to the efforts of his wife, Carmen Polo, and his daughter, Carmen Franco y Polo, Francisco Franco changed his will and declared in 1974 Alfonso de Borbón y Dampierre, duke of Cádiz, who was married to Franco's granddaughter, Carmen Martínez-Bordiu, as his heir.
Alfonso XIV's regime became "Pinochetized", as some historians point out today, as the new regime slowly moved away from the failed and hardly attempted democractic reforms carried out by Carlos Arias Navarro and became a de facto militar dictatorship with a king as a figure head that, eventually, would collapse in 1988.
However... What if Franco had decided not to change his will at all and allowed Juan Carlos de Borbón to become his successor. Would Juan Carlos be able to move away from the principles of the Movimiento and create a truly democratic Spain? Would the divided democratic opposition have accepted Juan Carlos as king if he had been placed in the throne by Franco's order? And, had he been successful in his attempt, would the democratic regime have lasted at all?