From: Connecticut, USA
Gotta love that HMS Hood - one of the prettiest warships ever, IMHO.
The designers of War Plan Orange seemed to take a strictly orthodox view over which aircraft would appear in the game, and when. They more or less enter at their historical times, and have their historical capabilities. That's all fine, but it neglects 2 important points:
1) Combat experience influencing design, which is understandable considering there WAS no war in the 1920s to do so.
2) The unavailability of British engines and weapons had a war between Japan and the UK broken out.
We can say that Japan has access to the British designs, and continues to build them locally even after the British stop exporting them. But before and during World War II, all of the major combatants came up with innovative designs. Some where successful, some were not. In some ways, WPO reminds me of what someone would have thought WWII would have been like if there been no WWII, only in the 1920s.
Also, in a war for their very survival, I don't think the Japanese would care one way or another about copyrights and patent infringements. And since Japan certainly would be capturing aircraft or scavenging wrecks - I really don't think they would have fallen so far behind in aircraft design as they do in the late game, particularly in 1928. Lets not also forget that designs for German guns and engines might also be available.
With this in mind, it becomes quite challenging to guess how aircraft design would be affected by a 1920s war, which probably explains why the WPO designers didn't bother and just stuck to historical varients. Unfortunately, this leads to absurdly unbalanced situations like Japanese fighters still mounting WWI era machine guns in 1929! But if a modder like Kirk ever wanted to tackle this, here's what I would suggest:
1) A mini-arms race in aircraft design, with advantages in engines, weapons, and airframes shifting back and forth between the combatants. Rather then designing entirely new weapon systems, I'd simply give very modest upgrades to the ones which exist (Mk II, Mk III, and so on).
2) The assumption that once a new weapon system is introduced on the battlefield, the technology will be available to the other side within 6 months. This does not necessarily mean that other side will be using enemy weapon systems, but it does mean that counters can be developed.
This goes way beyond what anyone has ever done with WPO, and requires a lot of conjecture and guesswork. But the results can be very, very rewarding. Just make sure that the aircraft don't get too capable and end up turning WPO into an aircraft game more then a naval big gun game!
If I had my way, a "research and development" phase would be added to WPO so the players could take direct control of aircraft development within the game. But of course, that would mean doing something for WPO that WASN'T already done for the War in the Pacific game it is based upon.
Not saying Kirk should to do this, as its could be a big project. But if I had my own game company, and bought the rights to WPO, that's what I'd be telling the developers to do. Just sharing some thoughts on this hazy summer day!