Three reasons why it would unbalance the game:
1) 60,000 lb of bombs for one formation.
2) 33,000+ feet altitude capability, combined with speeds of up to 355 mph.
3) One 20mm cannon and two .50 cal MGs in the tail. That means having to tail chase and close on a very fast bomber formation with double the firepower of a formation of B-24s.
Great for the Buffers, very bad for everyone else... Don't expect to see the B-29.
My regards,
Widewing