Saddam went into hiding...deep hiding...and we had to root him out of his underground pigeon hole.
Before that, we did not want to decapitate Iraq, and by the time we did, it was to our advantage that the Iraqi people try, sentence, and execute him themselves. Which they did.
But notice what we did to his two sons when we found them.
The Korean mad man is out in public often, and would make a target of opportunity we could get...if we wanted to.
North Korea has a system of tunnels and bunkers most likely the most extensive in the world. There have been may vet comment on those that where from and their extent and their engineering.