@Baron:
Here is the different values and ability brought up to enhance the popularity of AAA guns which I think can make a balance unit:
Lowering cost: 5, 4 or 3 IPCs. (2 was too unbalancing IMHO)
Varying the number of planes targeted: 1, 2, 3, 4, unlimited.
Allowing fire on planes first round only, or every round.
Allowing up to the max of 1 roll per plane…
Or just 1 hit per each AAA as a regular unit.
Allowing or not preemptive strike: first round, every round, none.
On planes only, and on Tank or Ground units.
Making it Anti-tank gun in addition (when no plane is present): target 1 or 3 Tank, on first round.
Adding a regular firing (when no plane) or after first round: A0D1, or even A1D1.
Allowing regular Move, not just NCM.
Making 2 AAAs units able to load on a single transport.
I think it summarize all the abilities. Did I forget something?
Based on all this above, here the interesting (from my perspective) combination of AAA gun developed here and elsewhere:
As a reference OOB:
A0D0C5 NCM1, 1 hit but auto-destroy if alone vs ground units,
preemptive targeting @1 up to 3 planes per AAA, whichever is less.
a) OOB Cost 4
b) OOB Cost 3
c) OOB Cost 5, up to 4 planes
d) OOB Cost 4, up to 4 planes
e) OOB Cost 3, up to 2 planes
f) OOB Cost 5, A0D1 when no plane or after first round. But regular 1 hit.
g) OOB Cost 5, A1D1M1 can attack and defend reg., regular 1 hit.
h) OOB, target preemptive @1 up to 3 tank per AAA, whichever is less.
I) OOB, target 1 tank preemptive @1.
J) OOB Classic, undestructible, @1 vs all planes, no hit, capturable.
k) OOB A0D0, preemptive @1 vs all planes, or preemptive @1 vs 1 tank.
l) OOB A0D0, preemptive @1 vs all planes, or preemptive @1 vs all tank.
m) OOB A0D0, preemptive @1 vs all planes, or preemptive @1 vs all ground units.
n) OOB A0D0, preemptive @1 vs all planes, or preemptive @1 vs 1 ground units.
o) J to n with A0D1
p) A0D1 cost 3, M1 on CM or NCM but cannot attack (it is for faster transport move), 1 hit as reg unit, preemptive @1 target up to 2 planes: 1 roll per plane max, reg D1 after (or if no plane)
q) A0D1 cost 3, NCM1, 1 hit as reg unit, each round can target 1 plane @1: 1 roll per plane per round max, reg D1 if no plane. Transport can hold 2 AAAs.