One man’s terrorist is another man’s freedom fighter.
Franco himself was from a region with its own dialect (Gallego), yet he still outlawed that in official business in education (he never tried to prohibit the use of dialects in general). He understood the regional dialects were a barrier to unity; Americans are learning the lessons of a common language today.
As for the “peaceful transition from dictatorship to democracy”, Franco himself was one of the most peaceful world leaders of his time. He avoided WWII, and his country enjoyed peace even through today. In the meantime, France fought the Indochina and Algeria wars, Britain fought the Mau Maus and the Malayan “emergency”, Portugal fought its colonial war (in three locations in Africa), and we fought Vietnam.