Unlikely. The situation is way different than that of the former East Germany. The North is a nuclear armed country and as has been shown the regime there would rather burn down the entire peninsula than get dislodged from power.
With completely different ideologies and system of government, it would be nearly impossible for south koreans to accept the leadership of Kim.
And for Kim, I don't think he (and the person behind him) would accept democracy.
In my opinion, North Korea is out of fund and wants some free treat.
Kim might accept North as a communist autonomous region of Korea where service and development funds are provided by the democratic korea but the region can opt out of paying the taxes.
I don't think the South would be happy with that nor accept Kim as the leader of a united Korea. And as you mentioned, the South has tasted democracy, I doubt they'd be happy to ruled by what is basically a theocratic monarchy.