My take on damper field has always been that % reduction is too binary, and it'd be more interesting as a mechanic if it was a +armor effect instead.
Basically, damper field gives just enough oomph to reduce the hurt when the ship is pristine, and when the ship is heavily stripped it can use it as a last-ditch attempt to stop itself from getting chewed by LMGs. 50% damage reduction on the mora, for instance, means that it would double its already capital-grade armor. Giving it a simple +400 armor, however, would make relatively little difference against dedicated armor cracking weapons like hammers, reapers, or hellbores, but it'd make the ship a LOT more capable of shrugging off inconveniently timed fighter or frigate strikes while its armor is already low. Unless they use harpoons.
it's an idea, and I'd be happy to let people tear it apart.
Interesting idea but I think you would need a lot more than 400 armor to make it comparable to the effectiveness of current DF. Percent damage reduction actually interacts with armor non-linearly.
Consider:
let armor = A, damage per shot = S, damage applied = D, damage reduction = r (a 75% reduction would mean r = .25 so its really r = (1-reduction)), extra armor = E
damage applied with a reduction is given by:
D = (r*S)*(r*S)/(A+(r*S))
damage applied with extra armor is given by:
D = S*S/((A+E)+S)
setting equal and solving for E in terms of r gives:
E = A(1/r^2 - 1) + S(1/r -1)
This is calculating the required extra armor to reduce damage equivalently to a damage reduction by r for a given A and S (ship and weapon).
for A = 500 (centurion armor), S = 400 (heavy mauler damage vs armor) and r = .5 (current value of damper field)
E = 1900 so you would need 1900 extra armor to get the same effect as current damper field vs a mauler (current damper field is considered bad on centurion).
This scales very non-linearly with the reduction factor though, so for 75% damage reduction (r = .25), you would need E = 8700 extra armor for the same ship and weapon.
It's also pretty clear why old mora with 75% reduction was OP.
With A = 1250, S = 400, r = .25 you would need
19950 extra armor to have an equivalent damage reduction. And for higher per shot damage values, it scales linearly so you would need 2x that much extra armor to see 75% damage reduction for an 800 damage projectile.
Solving for r in terms of E makes things easier to visualize. I don't feel like typing out the math but you will get:
r = S/(2*(A+E+S)^2) + sqrt(S^2 + 4*A*(A+E+S))/(2*(A+E+S))
Below I've plotted the equivalent %damage reduction for the centurion and mora as a function of additional armor and per-shot damage.
And a direct comparison assuming a heavy mauler (400 dmg per shot vs armor)
As you can see, there are diminishing returns on very high armor bonuses. Going from 0-2000 bonus armor gives something like a 55% damage reduction (for centurion) but going from 4000-10000 bonus armor gives something like an additional 10% reduction (70%-->80%). The Mora sees similar trends but at lower values. This again confirms how powerful 75% damage reduction was (imagine extrapolating the Mora curve out to .75).
Essentially the point of all this is to say that you would need very high armor values to get similar effectiveness to damper field. It does scale inversely with ship size though, low armor value ships will see a larger % damage reduction than larger ones for the same extra armor values. Maybe if tuned correctly, it could work, but smaller ships also have less hp so improved damage reduction means less (.65*400 is gonna get through a centurions armor/hp much faster than .5*400 will get through a moras armor/hp).