Apart from the fact it still leaves battleships as near as invulnerable to bombers, which is where we have the disagreement in the first place.
The fundamental problem is that a linear increase in turrets does not result in a linear decrease in damage potential.
0 to 1 Turret is a 29% reduction to 71% potential
1 to 2 is a further 33% reduction to 48% potential
2 to 3 is a further 40% reduction to 28% potential
3 to 4 is a further 50% reduction to 14% potential
4 to 5 is a further 67% reduction to 5% potential
5 to 6+ gives total invulnerability.
All the while, each additional turret gets MORE effective, when from first principles you'd normally expect an increase proportional to the ^0.5 power, and possibly diminishing returns on top of that, and to a large extent this is already represented by the turrets shooting!
If you take into account hull size, there's no significant reason T4 should be any better on a BB (subsequent to turret shooting) than T2 is on a Cruiser.
D6-T is just not fit for purpose.
Note: I am NOT trying to make Ordnance in general more powerful, except in the case of bombers vs battleships. I'm just saying that D6-T is nowhere near optimal. As it is, assault boats will score nearly as many hits against BBs purely from critical damage AND cause a huge number of criticals on top. There's just no incentive to send Bombers against BBs, even with fighter escorts, unless you have no other options.