Western style democracy isn't perfect, there are indeed many arguments to be made for a more authoritarian system that still allows people to voice their concerns as is present in Iran.
The government also has to fit the population, the culture, and the region. Right now what Iran needs most is to have its sovereignty protected, a more liberal democracy might not be able to protect Iran from outside influence aimed at causing societal degeneracy or to weaken Iran in general. Iran also needs to have the system of education and the industrial base of the nation improve to better educate and provide more modern jobs to Iranians, otherwise it's difficult to see how people are going to have the education and experience necessary to vote for who truly represents what's in their best interest. For democracy to work, people have to be equipped with the full set of intellectual tools necessary to distinguish which policies are most important to their lives, detect B.S. from candidates, and have the foresight and logical framework to be able to reason with themselves what is in the best interest of their nation in the future.
I understand people must be frustrated with what they see as lack of representation that being a citizen of other nations would afford them. But unfortunately, Iran, standing alone, with few allies, does not have the luxury today of no threat on its national sovereignty and culture.
And I also understand this desire to force everyone who does not want to be totally committed to the IRI out of Iran, thinking they weaken the nation. But brain drain is a problem worth seriously confronting. There must be a balance, some way to ensure the loyalty of Iranian citizens without marginalizing some group and forcing them to leave.