true, but Orlais have proven just as cruel as Tevinter in some aspects. The only reason why Tevinter need slaves is because the leading upper class mages need sacrificial lambs which are their slave because they use Blood magic most likely to control some of the population and battle the Quanari which they still are at war with.
If their slaves disappeared well the upper class mages would lose a lot of their power and the people would turn against them because the cruelty the people had to endure for thousands of years. In theory Mages could make a country without slaves, but in order for that to happen well Blood magic has to be made illegal.
Well, not really. Slaves are needed becuase they whole economy is based on slaves.
But yes, i theory mages can create a slave-free state. We haven't see one so far though.
I'm not saying that normals states are necessarily good though.
Ferelden's economy required the slave trade at that point in the story. That they were shipping instead of using is pretty irrelevant to the point. The point before was that Tevinter couldn't establish an economy without slaves. Well, neither could Loghain.
No, the point was that normals can create a slave-free state withotj collapsing. Loghain's situation proves that one country needed sell people to survive (in a particular situation). It doesn't change the fact that many normal countries aren't like that.