A month late in my response because I kinda forgot about this thread.
So SH5 (stock) has only 1 type of submarine the player can use with it's fully detailed interior. That's the Type VII, of which there is a surviving example in Germany that the devs could study in person (not sure if they did) during development. Consider the immense amount of detail that would have to be drawn in 3d to provide this level of immersion. Now there is a surviving Type II in Finland, one Type IX in Great Britain, one Type IX in the US, and a Type XXI in Germany. But those aren't in game due to the extra amount of time involved in modeling them.
Now let's go to SH4. Starting with the oldest and going forward: S Boats, P or Porpoise Class, Salmon/Sargo Class, Tambor/Gar Class, Gato Class, and Balao Class. Of those classes the only surviving examples are Gato and Balao class boats. Of those two, very few are still in their original wartime configuation. Add on the logistics difficulty for a European game developer to travel to the US for an extended amount of time, and frankly I'm glad they did as well as they did with the interiors we have.
SH3 had the same design layout as 4, or rather 4 follows the layout of 3. Of note as well, 3, 4, and 5 all run off of the same game engine. In fact when 4 came out, many of the files from 3 were still included but unused! I have a theory that I'd like to test someday about just how far down I can strip 4 and it still works as released.
SH2 gave us our first 3d experience in the series. The interior remained 2d interfaces but the exterior was 3d modeled.
SH1 was written for MS-DOS/WIN95. It was all 2d. Personally I loved the awards system from this and wished it could've been brought back with 4. You were awarded the real medals and could receive multiple awards of the same decoration. This was in stark contrast to 4 with it's fictional (US) awards and the generic baffling US aircraft used in game (Lancaster Bomber for the USN and USAAF).
As for playing Captain and crew, for a game, a balance must be struck. That balance was struck in 3 and 4 with it being optional to partake in other stations. Another thing to note, as I said earlier 3, 4, and 5 are off the same engine. That means 4 inherited the bugs left over from 3, 5 in turn was built off of 4. During development, most of us from Team "I'm the Captain" wanted those bugs resolved. We lost as far as I know. Trying to keep it informative here, but I know my bias is showing through. There's been a lot emotion surrounding the series since Ubi took over development. I bought 4 on release and shelved it after a short time of playing and didn't play again until much later. I also protested the paid patch that was the Uboat Missions before finally giving into that as well.