It's a very great TL, with very good moments (
¡Vayase señor Milans, vayase!; Rajoy resigning by simple political responsibility; Calvo-Sotelo becoming longest Presidential term of office, until the arrival of Zapatero; Zapatero being the reincarnation of OTL Aznar, being the beloved friend of the United States; Felipe Gonzalez and his first government becoming martyrs of democracy; and turn the Carlist pretender to the perfect constitutional monarch that Spain needs -and incidentally, to convince the British that they return Gibraltar to us-; Aznar being a charismatic leader who represents the yearning for liberty of the Spanish people; etcetera)
The only two things I missed in this story are:
1) Spain does not hold or the Olympics or a World Exposition in 1992 to commemorate the fifth centenary of the discovery of America (I fully understand your reason for the FIFA transfer the headquarters of the World Cup 1982, althought FIFA was already known by choosing authoritarian hosts them whenever they would satisfy its conditions; e.g. Mexico 1970 and Argentine 1978 at World Cup FIFA and Yugoslavia 1976 at UEFA Euro). After all, Barcelona 92 was officially appointed in October 1986 -when Aznar had already shown their intentions to effectively democratize the country- and Seville Expo'92 could have begun as a propagandistic maneuver for the semi-democratic regime, as did the dictatorship of General Primo de Rivera with the Expos in 1929, but eventually became another stage to show the world the progress of Spanish democracy.
2) that it hasn't happened a short Spanish-Moroccan conflict, to the Perejil style, which provoke the annexation of the former Spanish protectorate -that means the current Moroccan region of Tangier-Tetouan, plus Al Hoceima, Driouch and Nador provinces- during the democratic period "supervised" by the military, with Milans to head. Thus, the Spanish people could recover certain ties with its military and Milans and co. could vent without jeopardizing the incipient freedoms of the Spaniards.
By the way, could we know the fate of major Spanish politicians who couldn't occupy the presidential office? For example, Manuel Fraga, José María de Areilza, Carlos Arias Navarro, José Antonio Girón de Velasco, Nicolás Redondo, Jorge Verstrynge, Jordi Pujol, Xabier Arzalluz, José Bono, Rodrigo Rato, Antonio and Joaquín Garrigues, General Manuel Gutiérrez Mellado, Blas Piñar, Manuel Chaves, Esperanza Aguirre, Arturo Mas, etc., not forgetting other characters like Antonio Tejero, Pedro Almodovar, Josep Taradellas, Emilio Botin, Luis Garcia Berlanga, Ana Botella, Sonsoles Espinosa (who could want to marry one of her daughters in the Royal Site of San Lorenzo de El Escorial

), Isabel Pantoja (did she would rival against Ana Botella to get the popular nickname of "the widow of Spain"?

), etcetera.
PS: A question. What were the hosts of FIFA World Cups and Olympic Games since Argentine 1978 and Moscow 1980 (and winners of the FIFA World Cup)?
WC 1978: Argentine (Netherlands).
OG 1980: Moscow (USSR).
???
I am also very surprised that Japan has not taken the time of the Soviet collapse to buy or conquer the island of Sakhalin and the Kuril Islands. These areas have potential resources, and would serve to relieve the overpopulation of the Japanese islands.