[Wulfmann]

First, the dev has to consider what would be commercially successful and while a few might like being a Jap CO most don’t care for the above often stated reasons.
The majority that “think” they would like being a Jap likely know little about the poor boats the Jap subs were.
They were extremely slow to dive and a type IX is nimble by comparison to the poor maneuverability of these dogs. They were so structurally weak a good sneeze would sink one. Seriously they were weak, very very weak compared to US and German subs.
It might be interesting to run a few patrols to get an idea of how crappy boats are frustrating (even though they had great torpedoes) but it would not be long before you forget what side your on and care about having decent equipment and a snow ball chance in hell of surviving an M-80 or a couple firecrackers.
The Japs were big on making things photograph well and have impressive stats and their boats look good on paper. They are poor subs to actually have to use in combat, though.

Wulfmann