The idea that the Shah was overthrown for "too quickly" modernizing is a long-discarded myth. He like any other figure in history was complex. He had to walk a line between Iranian interests, and the realities which included Soviet threats, and that he was born into a project that his father started and which he was not necessarily interested in pursuing when he was placed in charge.

I would like to say it depends and it's kind of divided. I mean there is no doubt at all that Iran was massively modernized during his time in every shape and form. Many of those who initially revolted against him were either the Islamists who didn't enjoy his reforms which included things such as right of vote for women, access to education, more secularism and so on and the Communists, supported by the Soviet Union, who wanted to install their own government. It's worth noting though that the number of people killed/arrested/tortured during the time of his rule is greatly lower than what was happening in Western countries during that time. People bring numbers up to thousands but it is around 100 people in a nation of 30-35 million at that time during a period of 30-40 years, and few, if any, were arbitrary.