I can tweak of few things. All are D12s, except bombing damage.
Stg. Bomber
Attack 3, @2 (roll twice? for one round only?, each round?) roll of 1 no return shot (self-explanatory). Ground only
Attack 3 @1 (one round only? each round) roll of 1 no return shot (self-explanatory). Naval only
Defense 2
DF 1 (Dogfight?)
SBR 1d8+1 IC, Air-Naval ports, rail stations and oil refineries for damage
SBR 3, @2 (twice ?) single attack on AA gun after AA gun rolls defense first @2
Escorts and Interceptors allowed
Heavy Bomber
Attack 4 @3 (three times per round?) roll of 1 no return shot. For each Double 12s 1 friendly kill. Ground only
Attack 3 @2 (two times per round?) roll of 1 no return shot. Naval only
Defense 3
DF 2 (Dogfight?)
SBR 1d10+1 Same as Stg. B
SBR 4, @3 (three times?) Same as Stg. B Single attack on AA gun. AA gun gets first defense roll @1 if AA gun survives.
Escorts and Interceptors (NOT) allowed ?
I need you solve my question marks.
My first impression is that you follow a general principle that Heavy is better than Strategic bomber.
Are you sure that Heavy were more suited for Tactical missions than Medium Strategic bombers?
My rather limited understanding of all WWII bombers was that B-25 Mitchell or Twins Engines Betty (Strategic medium but not heavy bomber) were more able to bomb warships than B-24 or B-17.
B-17s were used in early battles of the Pacific with little success, notably the Battle of Coral Sea and Battle of Midway. While there, the Fifth Air Force B-17s were tasked with disrupting the Japanese sea lanes. Air Corps doctrine dictated bombing runs from high altitude, but it was soon discovered that only one percent of their bombs hit targets. However, B-17s were operating at heights too great for most A6M Zero fighters to reach, and the B-17’s heavy gun armament was more than a match for lightly protected Japanese aircraft
https://en.wikipedia.org/wiki/Boeing_B-17_Flying_Fortress
Based on this, I would agree that Heavy have a better AA defense in Dogfight.
Also, I would tend to increase the hit capacity of StB while keeping the double dice.
For instance,
StB treated as medium bomber
Attack 4, @2 against ground unit
Attack 4, @1 against naval unit
Defense 4, @1 (against ground only). (Same single die compared to naval attack.)
Dogfight 1
SBR damage: D8+1
Heavy bomber
Attack 3, @3 against ground unit
Attack 3, @1 against naval unit
Defense 3 (against ground only). (Same single die compared to naval attack.)
Dogfight 2
SBR damage: D10+1
You are adding a lot of little details between both, it makes it harder to memorize. I know your game have plenty of various units.
From a purchasing POV, I would need a clearer line to help me make my purchase decision.
For all bombers, an attack roll of 1 makes for no return shot.
I don’t see why bombers are able to destroy AAA. This feature might be an interesting capacity.
Is it a game POV or an historical POV?