Well, it is not our time, and it is not our type of economy. Sure, it is all nice and shit to free slaves, but when the economy is based on slavery, you can't just have every slave free and happy, while also having steady supply of goods and services. Dany was never exposed to any experience about how economic relations work. First they lived off money they got for the things they brought from Westeros, then they were provided by their merchant hosts, and later she lived with a horde that had only horses and stole/robbed/got as a tribute the rest. Right now what she has is a horde that does not tilt soil or do anything productive but wander around and attack cities. They are pretty much a blight upon the land, and three dragons burning herds of cattle do not help. Sure, it is a fantasy story, but there should be some realism. She executes free people who are architects, doctors, and such, and she will be left with a hungry crowd of slaves with no special skills. Unless she starts thinking about economy, how to have skilled labor, production and traffic of goods, stable food supply, and services, she is no more than a queen of thieves and robbers.
I know economy is boring, and dragons and conquests are far more exciting, but it is not a high fantasy where such things are irrelevant. From perspective of disruption of a normal life Dany is a frigging disaster, and she should learn to "count coppers" fast, or the entire Essos will be up in arms against her horde.