On it's own? Probably not.
BUT
The games economy has some weirdness right now and we've just had two DLCs focus on the east. It could very well be a good time to put out a triangle trade DLC. This is a decent idea since it effects gameplay on three continents as well as giving Paradox an excuse to dive into the economic side of the game.
Possible new slavery gameplay mechanics could revolve around having a "slave pool" similar to manpower, which would slowly increase from owning slave producing provinces (which would now behave like gold and no longer increase trade value.)
African and middle eastern nations could have the ability to take slaves from defeated enemies in peace deals.
Slaved could be sold for raw cash to other powers.
They could be used in the new world to increase colony growth or production development, in the middle east they could be used for Jannisaries or other things.
A while ago a thread was discussing that numerous African princes had actively fought the slave trade and tried to crack down on other African nations to stop the whole thing. This could be a decent time to represent this as a mechanic, if only to balance out an increased focus on slavery.