Unification will be a win win for the Koreas. Huge new markets, huge new resources, huge new labor pools...
But they cannot give the vote to the NKs all at once — that would be hugely disruptive. Maybe phase in the vote: First year, NKs under 19, second year, NKs under 21, third year, NKs under 23, etc. If things are going well, they can accelerate the process.
NK population is only half that of SK.
People will wonder why anyone was worried.
Why is it that they have to be one country?
It would be like trying to combine Canada and the US, even though we do share a common language. But North Korea’s culture is completely different. Better for them to be independent with close economic cooperation with the South.