From a Ghanaian friend who lives in London:

I would prefer a memorial to African Freedom Fighters. This will not only let us remember Europe's role in the trafficking of Africans which caused Africa's "underdevelopment", the wealth generated which financed the industrial revolution and help us understand how Europe became prosperous, but also focus on African freedom fighters and abolitionists.

This in my view is more empowering, and will go some way towards challenging the narrative of amorphous African victims of European enslavement.