...and the Swedes have very convincingly demonstrated that, even in the vast expanses of the Pacific, size doesn't necessarily matter, as their "loan" to the USN of HMS Gotland proved.
I'm sure someone's already brought it up, but for a submarine size is only relevant for its bunkerage or, in the case of nuke boats, to fit a reactor. Other than that the only reason to go bigger is to fit SSBMs.
The goal in fact has always been to make submarines
smaller but practical considerations usually get in the way. Nonetheless as with most naval vessels submarines are as small as they can get away with while still being mission-effective.