I am a bit curious where your ideas for the elite Impact Mitigation effect are going, given the 90% max mitigation being duplicated in Polarized armor. Where you looking for something that helps at high armor levels and or small weapon hits (which is what the 85%-90% does), but doesn't quite stack so much (1/3 less damage during the maximum mitigation period extends it by a factor of 1.5,.e. 50% more, while 2/3 extends it by by a factor of 3).
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Would something like a simple 10% more real armor, or +75/150/200/250 (tweak numbers as needed) real extra armor based on size, repaired instantly at the end of every engagement work? Where "repaired" is just the has an elite Impact Mitigation officer piloting it at deployment time, so it adds say +250 to whatever the armor was there as the ship is deployed into the fight. At the end, if it's over normal maximum in any cell, just remove excess.
I'm actually pretty open to what the effect might be - ideally it'd be something that's at least semi-interesting gameplay-wise, and also doesn't come with the problem of, for example, making most kinetics near-useless vs hull, like +150 effective armor did.
The issue with +X armor (not effective, just at the start) is that it wouldn't apply once command is transferred. Generally, the goal of the design is to have skill effects transfer over - although a couple do break that rule; most notably Missile Specialization. I kind of wonder - is "giving your intended flagship to an officer with Missile Spec, and probably Reliability Engineering, and then transferring command to it after deployment to benefit from about an extra skill's worth of stuff" at all a thing? I'd guess it's probably not quite worth it, but if we pile on more bonuses that work like this...
That is a fair point. Stack enough bonuses and some min-maxer some where will take advantage of it. I will admit if I'm pulling solo Odyssey shenanigans, I'll load it up with a missile expertise officer and switch into it, since my officers have nothing better to do in that scenario.
Interesting gameplay-wise is perhaps a bit tough given it has traditionally I simply take more shots to die kind of skill, which definitely makes the character or officer stronger, but doesn't feel like it changes the ship fundamentally.
Oh, how's this for a thought: damage to armor reduced based on current ship speed. The faster you're going, the more shots 'glance off'!
Balancing could be tricky, and might require scaling differently for different ship classes... but at least the notion of it seems good: a small benefit for slow, high-armor ships, a larger benefit for faster, less-armored ships, and a hopefully-noticeable boost to durability while Burn Drive is active.
Extra armor durability during Burn drive would be amusing, I admit, and potentially really useful. It does make it fairly niche though. There is quite a large range in speeds in each ship class, say from 25 of the Onslaught to the 70 of the Odyssey. Not to mention plasma burn drive. It also ties into gameplay.
What are mechanics and behavior we can tie into? Maneuverability, speed. Either modifying those numbers, or basing it off what you're doing (i.e. the proportional bonus to speed suggestion). There's weapons fire state, although that doesn't make much sense. There's shield state and flux levels. Polarized armor already has stuff proportional to flux level though. There's shield state though. Your armor could become better if you have no shields up (which would indirectly make damping field better). Reinforcing internal structures in a powered way somehow.
You could make the armor trade for winning the flux war explicit. You reduce your current flux levels by real armor lost. I.e. take a hit that make you lose X armor, reduce your built up hard flux by Y. If no armor was lost (i.e. it was all already destroyed in that cell) then no benefit. It does mean if an Onslaught eats a Reaper, it suddenly perhaps drops it's flux level by a few thousand. You're essentially storing waste flux in the armor sections, and if it get's blown off, it takes the flux with it.
Alternatively, increase flux dissipation while shields are down is perhaps simpler to communicate, and incentives actually armor tanking more.
Some crazier ideas: Ramming bonus when impacting on the ship sprite instead of shields, and reduced or completely negated damage from ship explosions.
Actually, for unshielded ships like Ramparts, or phase ships like the afflictor, being immune to ship/station explosions would be a fairly big quality of life improvement. You could alternatively simply limit how much damage AoE effects do to armor cells in total, so that things like Reapers still make holes, but they are smaller holes.