I was thinking of something around 4 seconds, reducible to 3 with skills, which the AI would not generally get.
Maybe I'm wrong about this, but - "assassin" builds kind of rely on phasing again to get away, no? And at times need to wait for the cooldown before firing the final shots to avoid the ship explosion. The window for what a viable attack angle is depends on how long it needs to be safe for, so it seems like increasing that would matter. Very much open to further thoughts/counter-arguments, though.
This sounds like a solid change to me. And agree with your comments on how it influences "assassin" builds, as far too often i've been overenthusiastic with firing last shots with a SO Harbinger and tanked a bunch of armour/hull damage from the resulting explosion.
"Skirmisher" builds need to be punishable, too, I think, btw... otherwise they're just in a "wait out their PPT" place
With the increase in phase cooldown times, i think skirmisher builds (assuming this means generally longer range builds that only phase to avoid fire.) then they could suffer from this, as they'd no longer be able to just flicker inbetween very narrow gaps in salvos and fire off their own weapons.
For example, you are in a phase ship, and taking
accurate constant fire from a single Hellbore (3 sec reload)
With the current 1-2? sec cooldown, you can easily pop in and fire a shot between rounds with no risk.
But with a change to 4/3 seconds cooldown, you are all but guaranteed to take a hit from it if you unphase.
This increased cooldown would notably lower the availability of safe windows you can use to fire from, which would be make defending against a phased ship lots easier. As you have longer to punish a ship after it unphases, so you could quite reasonably get a shot or two in before it can re-phase. And it means that you can much more easily "saturate" the space a phase ship is in, making it a bad idea to unphase, as currently with such short phase cooldowns, pretty much the only effective "saturation" weapons are the Hephaestus, Assault Chaingun and HIL.
For crazy shenanigans, make phase cloak decals a subsystem that can be disabled.
While this does sound good at first glance, i'm unsure if it'd really be fun in practice, it's not like you can knock out a ships shield projector by hitting it with EMP damage after all.