A one-time magical option is enabled for you to magically and instantly change all of the world's population so that absolutely everyone appears physically like members of a single randomly chosen ethnic group.
The single ethnic group will be randomly chosen and the random outcome (with each and every ethnic group having a probability of selection directly proportional to how much of the total global population they currently make up) will only be revealed AFTER your choice to do... or not to do.
So one possibility... is that you choose to do the Transformation... and then suddenly all over the world, everyone looks like a Serb and you are surprised (because of course, you had no idea it was going to be the Serbs).
What do you say? Let's roll the dice? Or let's not?
If everyone looks "the same," then at the very least we would get rid of skin tone as a source of discrimination for now although it is possible humanity will re-invent a new system of discrimination... perhaps linguistically, religious, or surname-based? You'd get a new world. But would it be a better or worse world?
Let's speculate. And justify your decision to do the Transformation, or not to do it.