The old way was to say, "The King is dead; long live the King." But I do not know that Thailand would be best served by another king. I just know it was well served by the last one. Many years ago when I was watching PACOM/SOCPAC issues professionally, I was continually impressed by how much better off Thailand was than its neighbors -- and how much that seemed to have to do with the wise guidance and steady hand of a good king.
Tolkien would have approved.