For the USA and Japan, the size of the Pacific meant that their subs had to have much longer range than those of the European powers. Habitability is also an issue for long cruises (and tropical temperatures). You can tell the crews be tough, but no matter what efficiency suffers if you ignore these issues. As noted, the major problem is to change Japanese submarine doctrine, absent that technical changes are almost irrelevant. The other major problem is that while Japan is highly dependent on imports that have to pass through restricted and well defined waters. On the other hand, the US has a lot of coastwise West Coast traffic, but during WWII not much in the way of incoming traffic from the Pacific to the West Coast. Once you get past Hawaii, the routes to various places like Australia/New Zealand, various islands are quite long, can be shifted a little, and cover a huge area for a submarine to search.
If the Japanese do adopt interdiction strategy, and they develop "milch cows" to help maintain subs at a distance, and improve habitability, etc of subs, it still won't really change things. To be effective the Japanese would need many, many more submarines than they had to cover such a vast area. They simply cannot build that number, even if they start well before the war - what ships WON'T they build to build more subs? Frankly any ship type, including merchants, they short to make more subs will make things worse for the IJN. A better doctrine, and a few changes/new subs would help, but not that much. The USA can shift a little construction for escorts for the Pacific if need be.