Unless, and this is a BIG unless, you are the ruler, ie the Empress. So what you are defending here is not justice but rather what you see as a benevolent dictatorship.

Oh, and you better hope that your baby daughter isn't born with the Spark or she'll be taken away to live life as a possession.

The Seanchan order comes at the price of a slave-nation mentality. One necessitates the other. Remove the slavery and order will begin to break down as people realize the Empire is not always right.

Not that the feudalists in Randland are better, but to say Seanchan society is perfect is blinded at best and delusive at worst.