Japan, China and Iran for sure if travelling for culture and history.
Have yet to travel to Japan and Iran, but have travelled quite a bit in China, but far from enough. One of the more interesting country to travel, but most important historic places is quite busy and crowded unfortunate.
Not so many other Asian countries I have the desire to explore anymore. When I go now, it is more for holiday and food experiences, and rank Kuala Lumpur for some of the best international Kitchen in Asia, not so bad in Dubai either, but Dubai Im done with.
If I would go on a new expedition, it would be Malasia and Indonesia Borneo, and Papua Ny Guinea