Another idea to consider would be a WWII merchant Marine simulator.
Give a taste for the other side of the war.
A game where you have to make decisions concerning whether to use convoys or single ships and if so, how to structure convoys with limited resources all the while being faced with demands from both suppliers and delivery forces for more and more.
As the war progresses, these decisions may need to be modified.... or not depending on the player.
How to plan what the escorts will do if the convoy is attacked (there are some really good books that describe the various techniques for escorts and how it evolved in the war)
Figuring out the courses and speeds to enable efficient shipping while still avoiding being too predictable.
Just the logistics of forming a large convoy is pretty complex. The player would have to weigh any advantage of a convoy with the vulnerabilities of forming and disbanding convoys.
If using a convoy how to implement OPSEC. And if attacked, what will the convoy do and how will that effect crew morale?
I would be interested in playing that sort of game. Be nice to do some historical "what ifs" concerning the decision to use convoys and when to use them.
That sort of game might be a good break from the killing type games.