It may be a little late, but here's my opinion anyway.

Even if Erdogan is a power hungry a-hole, a coup is never the answer when there are democratic means available. Unlike places like Russia and Syria, Turkey is still a democracy, albeit one under threat and with numerous problems, and the government does not fully control all aspects of the country. When the country is a full dictatorship and the autocrat/autocrats in power control absolutely everything, that's when a coup can be an answer.

However, military coups are another matter. As someone who lives in a region (Latin America) that has seen countless military or military-led coups (my own country, Venezuela, has had at least 3), I can tell that when the military deposes a government, they usually keep power for themselves. I can only think of one time when the military of a country overthrew a government in order to restore democracy (my own country in 1958, when a faction in the military deposed dictator Marcos Pérez Jiménez, himself a general).

PD: Even if Erdogan's government is legitimate, purging tens of thousands of alleged opposition supporters from the civil service is still a bad thing.