Imo torp carrying B-25s would have been developed if a need for them was demonstrated. It wasn't.
Torpedo armed B-25s WERE DEVELOPED. That seems to be the key point you've overlooked. USMC B-25 drivers were trained in torpedo attack from 1943 onward. But since the Japanese were on the defensive, torpedo strike missions delivered against Japanse targets were by circumstances limited to the fleet carriers, because these were the offensive weapons that carried torpedo bombers into range against the IJN.
If there had been a protracted defensive war on the US part, or if the combat had gone long in the Malay barrier, or brought the IJN into close proximity of places where the USN could not easily react, such as the Indian Ocean in 1943, torpedo armed B-25s would have been deployed there.
You apparently think it was a simple and obvious tactic and weapon. Really? I say again that there were a LOT of very smart people fighting that war on all sides. Surely this tactic was seriously considered and rejected for a variety of reasons--poor results, too expensive, too sophisticated to use in mass quantities, not enough ordinance, too many pilots and planes were going to die flying low and slow into flak....the list I'm sure goes on and on.
Torpedo bombing by B-25s was not "considered and rejected" by the USN. It was "considered, deemed to be a good idea, and a training program was developed whereby USMC B-25 drivers were intensively trained in torpedo attack." You need to study up on the history here.
I prefer to play the game with the tools and tactics the commanders had to use at the time, which I think the game developers have done an admirable, if not perfectly perfect, job of creating. Creating a B-25 torpedo bomber is reinventing a hammer if not the wheel, but I suppose that's what some folks like mods for...fantasy.
The fantasy is that B-25s were never considered for the job. Again, you need to do a little research. USMC B-25 operators were trained to use B-25s in torpedo attack. Circumstances did not require their use in that role, but the fact that USMC medium bomber crews were trained in torpedo attack through the end of the war proves that the USN not only considered that B-25s might be needed in that role, but also anticipated it enough that B-25 crews flying for the Marine Corps were trained in torpedo bombing. You really need to do some research before you dismiss a historical fact as "fantasy."
While you're at it, give the B-17 a torpedo load out. That surely was a possibility, so we should clearly be given the option.
Why would one do that? The USAAF did not have a doctrine or training program for B-17 torpedo bombing. Your comparison is invalid because the USMC DID have a doctrine and training program for B-25 torpedo bombing.
If you're really interested, scroll back a little in this thread and look at the B-25 picture that I posted. If you know your apples from your oranges, you will see that those B-25s carry a torpedo. That's the long object with the nose ring hanging close to the fuselage on the starboard side.
Show me a B-17 unit trained in torpedo ops and I will suggest that B-17s be given the option too. IMO, B-17s should be allowed to skip bomb (because it was B-17s that first put skip-bombing into operational practice in the Bismarck Sea). But I can find no evidence for B-17 torpedo bombing.
Show me a fellow who rejects statistical analysis a priori and I'll show you a fellow who has no knowledge of statistics.
Didn't we have this conversation already?