Played the 1941 scenario last weekend. USA, monarch.
Interesting setup, I like especially like the fact that workers are used after terraforming and it takes a huge amount of turns to do so.
The war against Japan was (too?) straight forward. The AI is really bad in handling its fleets and whatever numerical advantage it held at the start of the scenario didn't do a lot in the end. The AI tends to leave its sea units alone, making them easy pick for hit and run tactic using classic SOD gameplay.
This reminds me of the same gameplay problems I've experienced in similar CivIII mods/scenarios. A few things that should be done:
1) Sea units cannot leave and enter a sea port in the same turn. They must stay at sea a full turn. This gives a chance for the AI to counter-attack your fleets.
2) Implement some form of stacking limit for sea units. A stack with 2-3 BBs, 2-3 CAs and 1-2 CV with full implement of fighters is way too strong in the current state of the mod.
3) Sub needs tweaking. I would remove their ability to see other sub. In fact, the only unit that should be able to see and attack sub should be destroyers and air units. Also, I would give sub the ability to choose their target in a stack.
For reason I don't understand, when sub attack a stack with sub in it, the defender is always a sub. That's just silly. The changes mentionned above should correct this.
4) I'm sure for the sake of simplicity, or my lack of knowledge of latter units, there a just a few type of air units at the beginning of the scenario. For carrier, I recommend a unique type of fighters which would represent a combination of interceptor, dive bombers and torpedo bomber. Land based fighters should be different than carrier based one's.
However, the introduction of land-based naval bomber units would be nice. Perform at -50% against land target, cannot bomb infrastructure/improvement/cities and normal strength against naval units.
5) Restrict the range of air units when rebasing. Make it like 2 or 3 times their operationnal range. I shouldn't be able to rebase air units from the pacific to the atlantic in a single turn.
6) Considering the size of the Pacific map, I feel that sea units have too many movement points. It's too easy to move around with big stacks. Air power does not reflect well either in the current setup. Their range of sea units is too high compared to the range of carrier based fighters. It would be nice to have carrier fleet engaging each other with their air power but they are unable for classic fleet action because they wouldn't have enough movement points to engage each other with sea units.
The pacific theater of operation for WWII was all about air power. Currently, carrier based air units do not have the range to attack an enemy fleet without retaliation by normal sea unit. Carrier move at 4, fighter attack at 3; effectively a range of 7 which is a range easily attainable by cruiser and sub since they move at 6.
7) Sea units have too much line of sight. Again, this is especially obvious since the pacific area is not that big. I would restrict the LOS of all sea units to 1, set it to 1 also for fighters, remove that option for bombers. It would be nice to have more a sense of hide and seek in the ocean with sea units. This would greatly increase the value of intelligence: the first side to spot the enemy fleet increase its odds to inflict damage on key enemy units.
8) If the above is done, introduce air units that can only perform recon mission
9) The tech tree is confusing. I would remove all early tech that are shared by all countries and redesign the dependencies. In its current state, it is very difficult to understand the dependencies. They are too many lines.