I would tend to agree with the unification of Korea as being a good thing. So would most in the region on the proviso that the regime of Kim-Jong-Il came to an end as a result of that reunification.

If Japan can live with a vibrant and energetic emerging China (Japan has to because it can't do anything about it) a unified Korea poses no threat to them that they (Japan) haven't faced before. A reunification along the same lines as the reunification of Germany would be welcomed politically in Japan - they wouldn't then have to have debates in their Parliament about changes to their constitution to allow them to attack one of their neighbours.

The US, Russia and China in general gave up "playing dirty divide and conquer politics in the region" decades ago, this was just LH's usual anti-American dig. All would welcome the departure of the regime in the North, it has become a truly dangerous embarassment to it's allies (Russia and China) and as Kim-Jong-Il continues to play his blackmail games with diminishing effect (Now all parties agree with the US approach that no bi-lateral talks should take place with North Korea, it should involve all six parties) North Korea becomes more dangerous in respect of what it would be prepared to sell to who in order to get hard currency it needs to keep the regime alive.

Under any reunification process it would be the leadership in the North that would lose out, no one on the Korean Penninsula would opt for Kim-Jong-Il's, or Stalanist Communism. The only group of people I believe oppose reunification are those "Governing" North Korea.