From: Iowan in MD/DC
One of my favorite features from my previous WW2 Pacific game (PTO 2!) was the ability to choose from 3 campaign start dates - 11/30/41, 5/27/42, and 3/31/44. After a while, the only way to get any sort of challenge out of the game was to play as Japan in 1944 or 1941, or as the US in 1942, with various difficulty settings.
To me, that is the biggest hole in WITP:AE. A campaign start just prior to Midway (5/27/42...) or Coral Sea, or one that's just after the conclusion of the Guadalcanal campaign (early 1943), would be ideal.
While it's interesting to rehash the early phases of the war, particularly as Japan and playing around with different offensive strategies, it can be just as tedious as it is for the Allies. It would be nice to start 4-6 months in, with the historical Japanese expansion already reached and with the Allies finally organized for war. I once opened up the Editor to try to give it a go myself, but decided that the interface wasn't intuitive enough for me to bang it out in a week or two, so I gave up.