It would be
possible. BUT!!! The 1st things you have to ask yourself when considering it are:
1. Do I
need 3d model of the submarines I'll be commanding. If the answer is "no" you've just saved yourself a ton of work. Tweak and rename current US subs to specs used by specific IJN sub classes and you're part way there.
2. Do I really want to create a campaign? Creating basic campaigns are really more of a pain than anything once you get a feel for how things work. It does take a lot of time--huge amounts if you want it done right.
3. Enemy AI: All the sensors for Allied esorts would have to be checked out if you want accuracy. All the Allied escort vessels as well would need thorough checking and testing. really not such a bad job until you begin to find problems

... And consider these sonar types: Type 123, 128, 144, 147, QCe, QCa, QCg are active sonar systems used by the Allies in WWII. And that's just active sonar. the list for radar systems is longer. All need to work.
4. I'd like the challenge and option to do what you're asking BUT (another one

) I know that it would likely be a suicide ride. IJN Submarines that were most likely to survive are the ones that hid. Agressive ones were dealt with teardrop dc's, Hedgehog, Excellent sonar, Ubiquitous Airborne radar and..... Not many located IJN submarines had a chance from 44 on.
In short--it's serious buggar that someone may attempt/do at some point. I think all the nessecary elements exist in the sim to make it a reality. Just please don't ask me to do it

.
Peto