My impression is Allied Fleet can't do nothing until it's upgraded to naval weaponry 2. Other impression is that carriers and their might is overpraised. In my game with Roy, actually Cruisers and Battleships did the job, from bombarding the shores of China (the only thing that could actually stop Chinese there was this devastating fire, costed me few divisions until I realized getting land Chinese unit on a shore hex will end up as a target practice for Imperial Fleet) to wiping out enemy's ships.
In end of 1942 I was trying to weak Japanese fleet a bit, and result was in Battle at Java Sea. On the picture below you can see allied fleet AFTER they attacked Japanese ( I recall I sunk one destroyer and damaged a cruiser). In his turn Roy just unleashed all his firepower and literally wiped out every allied ship you can see on this map(expect one destroyer). That was a disaster, however US NAVY was bought time to rearm.
In one year, situation turned over. When the same Japanese task force was trying to stop American Invasion in Philippines, It was a true kamikaze mission - whole US NAVY upgraded destroyed most of the attackers. The sheer numbers of US fleet was 3 to one in my favor I guess. What is interesting, US carriers played only additional role. Actually, American, upgraded to level two cruisers and Battleships did the job.
As from strategic perspective - "meat grinder" tactics favor allies, I was deliberately attacking (and losing many troops) on all fronts, to confuse my opponent, so he couldn't tell where is my schwerpunkt, and to bleed him out from precious MPP's. In China buying additional HQ for southern front and sending just a three allied air units was enough to drive Japs back to sea, although it took some time, because I couldn't even get close to the coast hex, afraid of Navy bombardment.
As for game:
Why can't I, as Allied player strategically move air units on the pacific Islands? When I took Ivo-Jima, I couldn't put my fighters there:/
All my opinions are just my thoughts, a feedback that may help this great project develop further!