Best possible outcome for Iran with a POD after 1900?

Iran has had a tumultuous 20th century history. Many revolutions, coups, conflicts. What's Iran's best outlook in terms of economic growth, quality of life, political stability and at least somewhat of a democracy?
 
Not overthrown of Mossadeqh. He might transfer Iran to more democratic direction. Or at least remove Mohammed Reza Pahlavi by early 1970's and make his son shah.
 
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