Isn't the specualtion interesting?
If the US had had that LA class submarine during WW2, in my opinion it would not have affected the course of the war at all. Why? Because it has 4 forward torpedo tubes and as such, a small firepower when attacking merchant ships (Only could sink four each time, plus reloads) i.e. nothing much different of what the Balaos could do. The Harpoons wouldn't add much here.
Admitting that the Tomahawks could serve well for attacking land objectives, again this is nothing that a good traditional carpet-bombing from Airplanes couldn't achieve already.
Only the nuclear bomb would have changed things (Missiles with nuclear capacity), but not the LA class itself or its conventional weapons.
And then, the complexity in the construction of LA class submarines would have meant that with the same effort, less of them could have been produced (Balaos were constructed from preassembled parts in a row).
Therefore, I consider that for the US in WW2 it was of more use to have had 400 fleet submarines that for example 100 LA class boats. Sure, the LA class wouldn't have suffered losses, but as a theoretical exercise it gives interesting results, doesn't it?