Specifically regarding the bombers: If the B29 is a 2, and the Boston, G4M, Ki-67, etc, are a 40, me thinks the Lancaster, B24, and B17 could use an adjustment in ENY and OBJ scores. The gap is simply too big, imo. Also, the Lancaster, B24, and B17 could all use a small perk cost as well considering their ability to lay waste to targets. Think of the offensive capabilities, think of what they can do. I know some will speak up regarding the Ar234 and Mossi B Mk 16 and their speed, but when was the last time anyone panicked when they saw a flight or 3 of Ar234's or Mossi B Mk 16's? I'd much rather see a flight of Ar234's roaring over my airfield than a flight of B17's. The speed demons are ultimately 1 pass wonders and wont be hanging around. The Lancs, B24's, B17's, etc, can spread their damage over a much larger area and loiter for a lot longer thanks to defensive capabilities and escort benefits.
On suggesting a perk price for the Lanc, B24, and B17: currently, players keep banking earned perks and they ultimately have very little to spend their perks on (aside from the B29). I say give the other heavy bombers their due and add a 1-2 perk cost to them, AND lower their ENY. Remember, escort fighters in WWII were common so the "bombers are defenseless" argument is a double edged sword in AH. Use escort fighters.