how about this:
every I.C. on the board is actually a liability, but some are less costly than others. in many player’s opinions, maintained strategic bombing raids by heavy bombers is the most powerful attack possible in the game, since it has the greatest potential to unbalance the game in favour of the attacker (followed closely by sudden attacks on stacked naval units by newly acquired heavy bombers or long range aircraft). such an attack allows a player to remove his opponent’s units from the board at a faster rate than the opponent can replace them, and at a greater rate than his opponent can remove his units from the board. in other words, it is a winning strategy that can only be countered if the opponent is also able to acquire heavy bombers.
Since I.C.s do not produce any value in and of themselves, it follows that owning any I.C. is costly rather than profitable. unfortunately, most original I.C.s are located in capitals or other tactically important territories (karelia, etc.), so abandoning them is impossible (not to mention that they are important for getting new units into play). therefore it follows that instead of building new I.C.s, alternative methods of supplying units to the front line must be used. the standard method of doing so is by using transports with usa, uk, and japan.
the least costly I.C.s in the game are in japan and both eastern and western usa. these cannot be easily reached by bombers from the opponent’s territories, unless the opponent has captured, say, alaska or mexico or manchuria, at which point the game is probably decided anyways. somewhat more costly is the I.C. in the uk, which can easily be reached by bombers from germany, and slightly less easily by bombers from japan. in the middle of the spectrum are the I.C.s of germany, russia, southern europe and karelia. all of these are very easily accessible in that any of the powers can easily send bombers to run SBRs on them. however, since some of these I.C.s are allied and others are axis neither side is intrinsically in a costlier position than the other - there is a balance maintained by an equal level of susceptibility to SBRs.
by far the costliest I.C.s are the ones which japan and the united states build that increase their susceptibility to SBRs. for these otherwise isolated and protected nations, building I.C.s in manchuria, india, burma, sinkiang, finland, alaska, etc. makes them tremendously more in danger of a long-term bombing strategy. in order to maintain an equal playing field players must not build I.C.s in those locations. if someone does build there, i would suggest that it is an immediate advantage for his/her opponent.
all that aside, certain I.C. builds might actually be profitable. losing a british I.C. in india to japan might seem to be a terrible prospect, however since it could provide an otherwise unavailable target for bombing it could just be a winning tactic. the same might go for an american I.C. in china or sinkiang. i have even seen a move by a top pbem club player in which the americans built an I.C. in mongolia knowing that japan would have to take it in order to advance their lines towards moscow. japan was trapped by either allowing allied units to be built directly in asia or by opening themselves up to a brutal SBR campaign.
i never build I.C.s with japan or the usa. as soon as i see my opponent build an I.C. with either of those countries my strategy shifts towards tech rolling and a quick win.