TLDR; the skill is a bit better than damage control as it currently stands because it has comparable hull savings but also armor savings. It is better against smaller incoming shots and significantly worse vs large incoming shots for stopping hull damage.
I do think the skill is weaker than it was, but I also think its still a pretty impactful skill. Since the change I have still used low tech ships effectively to beat endgame threats and in many ways its easier because said threats aren't immune to kinetic damage anymore. If the skill needs a buff (and I think sure it could use a small one, why not) I've suggested in the past adding back the old minimum damage reduction of 10% from 15%, making armor tanks less susceptible to minimum damage from small sources
As for is it worth taking elite:+50 armor reduces mid caliber incoming damage to hull by an amount comparable to damage control, with a % comparative reduction equal to: 50/(d+r+50) where d is incoming shot size for purpose of armor reduction and r is residual armor (5% base armor). d is effected by the -25% armor damage if I recall correctly.
Some numbers: vs a 100 penetration, 75 after skill shot:
250 armor -> 36.4% relative reduction in hull damage of taking elite over not elite
500 armor -> 33.33%
1000 armor -> 28.6%
2000 armor -> 22.2%
vs a 200 penetration, 150 after skill shot:
250 armor -> 23.5% relative reduction in hull damage of taking elite over not elite
500 armor -> 22.2%
1000 armor -> 20%
2000 armor -> 16.67%
It is still one of my "go to" elite skills. Its not a game changing effect like elite phase mastery, but it is better than many elite skills.
Changing +50 to "double normal" is an interesting change because its a further nerf for high tech ships relying on the skill to tank kinetics, but a decent buff for capital ships (and dominators). The relative % damage reduction caused by this reduces to an even simpler formula: r/(d+2r)
Same numbers as above:
250 armor -> 12.5% reduction to hull damage from pulse laser (75 penetration) elite compared to not elite
500 armor -> 20%
1000 armor -> 28.6% (same)
2000 armor -> 36.4%
vs a 200 penetration, 150 after skill shot:
250 armor -> 7.14% relative reduction in damage of elite compared to not elite
500 armor -> 12.5%
1000 armor -> 20%
2000 armor -> 28.6%
So the proposed change would really eliminate the value of the elite skill for high tech ships: on the other hand, low tech armor tanks would love it.
The total damage reduction to hull given by impact mitigation (with elite) simplifies to a slightly more complicated formula: (.25r + 50)/(.75d + r + 50)
Numbers vs 100 shot size:
250 armor -> 38.6% reduction in hull damage of the elite skill vs no skill
500 armor -> 37.5%
1000 armor -> 35.7%
2000 armor -> 33.3%
vs 200 shot size:
250 armor -> 25%
500 armor -> 25%
1000 armor -> 25%
2000 armor -> 25%
Well isn't that neat, its a constant! And equal to the Damage Control numbers! Cooooool.
vs 500 shot size (heavy rounds now)
250 armor -> 12.1%
500 armor -> 12.5%
1000 armor -> 13.2%
2000 armor -> 14.3%
There we go: heavy shots start to get through Impact Mitigation.
So, in comparison to Damage Control, just the hull damage mitigation portion of Impact Mitigation is superior for shot size below 200, and inferior for shot size above 200. It gives -50% damage taken to weapons and engines instead of +50% faster repairs: better for small amounts of incoming damage/emp, worse for overwhelming amounts where the weapon is going down no matter what.
So to me it seems like Impact Mitigation is roughly equivalent to Damage Control, just better against medium ordinance and worse vs heavy, without taking into account the skill actually protecting armor as well as just hull. So its a moderately superior skill as it stands to damage control.
Or take both and stack that hull damage mitigation and weapon uptime modifiers to quite high levels.
