Japan 45

[Green]

What I am doing for Coronet '46 is reduce the bunkers to a "+20%" (meaning build them to +40% but then remove the units from the location to reduce it to +20%). They are still tough to take but this reflects the ability of the Allies to burn out the inhabitants. It was either that or have each engineer unit (for the most part) have a huge Assault rating. I chose the latter method.

I do not know the numbers but it the majority of bunkers are going to be setup using their Vacated values, why not just set lower bunker values in the .pdt file? That way when they are vacated and reoccupied they will be less useful (to either side). Otherwise, if the Allies capture a bunker it is effectively undamaged and immediately as useful to them as it was to the Japanese. Hard to imagine this generally being the case.   

If there are a minority of bunkers that you want to initially set at their full value (what you refer to as +40%, but presumably you mean -40%), then you could use pillboxes with their Vacated value instead. This would give them -20%/+10 (pillbox) as opposed to -40%/+10 (BUNKER) but this may be a reasonable compromise. Obviously both bunker and pillboxes values can be tweaked to any values that make sense but I would have thought that the concept that they are less effective when reoccupied should be something that still applies in the majority of cases.