Easy fix...
Fighters have a 5+ resilient save when attacking fighta bommaz. Fighters which have resilient get a 3+ against them.
Fightabommaz should be less effective (Shitty) against ships, and having half as many as attacks makes them exactly that. You making them only get 1 attack makes them completely worthless. If they act like suicide craft like you have stated, then shit...they should act like giant ass torpedoes and do a suicide ram so should always wound on a 4+ if they only get 1 attack.
As they sit now, they are half as good as regular bombers, but slightly faster, and the same as fighters just slower.
How about this...
Bombers have 6 attacks, Fightabommaz have 3, get rid of the dice rolling on it. Still use turret suppression rules, but fightabommaz can't suppress turrets, but they still get 1 attack each for each being fighters as well as bombers.
So with a wave of 4, of each type hitting 5 turrets...
Bombers = 4 attacks
Fightabommaz = 4 attacks
Wave of 4, of each type hitting 2 turrets..
Bombers = 16 attacks
Fightabommaz = 8 attacks.
Assuming nothing is shot down..
With this, they are exactly the same as regular bombers as large craft, however they are half as good against regular bombers.