Indentured servitude is slavery. With the only caveat being the promise of "eventual" freedom
Interestingly, one time in Bioware's history where slavery wasn't presented as an unmitigated evil.
The only case we know about in the rest of Thedas of indentured servitude being practiced is in DA2, where Hawke and family enter into this arrangment for one year to pay off whatever group bribed the guards to cover their entrance fee into the city.
So either indentured servitude is legal in the rest of Thedas and they do make a distinction between it and slavery... or it's just as illegal and Hawke's situation was more of a gentleman's agreement to work off the loan for their creditors directly?
I'd add it as another "positive" example, since while they didn't enter into the arrangement without reluctance, Hawke's creditors did let them go at the end of their year of service and consider the debt covered in full. They could have easily ratcheted up the price (or in this case the period of time) to cover the "interest", as so often happens when people are in debt (especially when it's to loan sharks).