@CWO:
Many of the island territories in the Central Pacific which Japan and the US fought to control were little more than coral atolls, volcanic formations or overgrown sandheaps, many of them small in size and some of them barely above water at high tide. They had few (or no) natural resources, little (or no) arable land, few (or no) indigenous inhabitants, and no industries; the military bases located there had to be supplied from outside with virtually everything they used. **They were for most practical purposes 100% consumers and 0% producers. **
The value which these islands had wasn’t as industrial production facilities or as sources of income or of goods or of raw materials. Their value was to serve as airbases (and in the case of suitable anchorages like Truk as naval bases) which allowed the domination of the airspace and ocean around them, and to serve as the jumping-off point from which to capture the next island group down the line. So if the rules provide no incentive to capture and hold these territories, the historically realistic solution isn’t to give them an IPC value. The solution is to create a house rule through which possession of an island gives some sort of bonus to a player who uses the island to attack enemy forces around it or as a springboard for an island-hopping advance.
From a geographical point of view, we can say that the board shows islands group not just isolated one.
Nevertheless, they are not economical centre for sure.
But here is my point of view:
IPCs with NOs can somehow represent strategical & political objectives which receive their reward when the goal is achieved.
Economically, it is also a way to go under the 1 IPC/territory limit fixed by the board.
(If all 1 actual IPC was converted by x10 giving 10 revised IPCs, it will be easier to assign an actual .5 IPC value to an island territory: becoming a 5 revised IPCs, etc.)
Because a Power must hold 5 territories together to gain access to 5 IPCs and loosing anyone means it loose these 5 IPCs income next turn.
So it takes time to get the 1 IPC/territory income in this situation and can easily be lost.
It is not historically accurate to give some islands groups a regular IPC income, that’s true.
But it can be correct to view it as a momentary boost on overall morale due to strategical success that allow a one time IPC bonus to get it.
So you get 1 territory, you get a one time reward : between 2 to 4 IPCs (to adjust).
You keep this territory thereafter and it won’t give anymore economical boost.
Reversely, you lose 1 territory, you get a one time penality: 1 or 2 IPCs.
I think it can also be acceptable to joined together many territories and give them an overall value when all of them are conquered.
A Geo-strategical advantage can be somehow implied in an IPC bonus.
At the end, more IPCs you will get you additional units which can give an edge over the enemy to better enforce some strategies.
Maybe some NOs can also be a one time bonus success.
And loosing some NOs can also mean getting a one time penalty.
Of course, when one or two key territories going back and forth means gaining and loosing every turn a NO, it could create an economical conundrum.
But, usually, the Pacific battles are not like the Russian front.
Of course, what I say here is just some rough draft ideas.
It will need much more fine tuning to get a balance incentive for PTO action with IPCs bonus and malus, combining NOs and one time immediate reward or penalty for taking or loosing an island territory.