Look at it this way, in a WW2 flight sim you not only want the mainstays of the various airforces. How often have we not flown around in FW190, ME109, Various Spitfires, Hurricanes, Tempest, Mustangs, Zeroes etc.
The esoterics add flavour and variety. Not because they are necessarily better or even on par with the more famous aircraft, but because they are different. Just take'em out for a spin and see what they can do.
edit: Come to think of it, after the devs have patched up the game, they should release an expansion pack with more allied subs _and_ incorporate an IJN campaign (with jap subs obviously) where we can play around as nipps. That would be cool
I'd buy it in a heartbeat.