Answer:
It would be nice.
But you have to notice how the situation differs from East/West Germany.
1. West Germany was richer than South Korea
2. East Germany was much richer than North Korea.
3. East Germans actually had an idea of what the world was like on the other side of the wall.
4. East Germans didn't have a psychotic leader.
The simplest answer is to say that economically that south Korea can't absorb the North without severe problems.
But the real problems arise from 3 and 4. Kim Jong-il will not voluntarily allow unification to happen. Even if he disappears, the citizens of North Korea are not familiar with life in a modern capitalistic society. This will lead to situations where each will take advantage of each other. Eventually this will lead to class warfare to start with and total political anarchy eventually.
Points.
5. West Germany had a much more stable political system than South Korea.
6. East Germany had a much more stable political system then SOUTH Korea.
South Korea needs a few more decades of stabilization and maturation before such a situation, if even it could be possible, could be safely achieved.
People seem to give South Koreans a lot of credit because they are successful in Industry and making a buck, but socially, I don't believe South Koreans are going to be able to be mature enough to accept the North Korean society in a selfless way.