[deathspeed]

But in terms of the different kinds of countermeasures, I was thinking of a very old fighter combat game! I hope this makes a bit more sense.

Microprose's F-15 Strike Eagle on my Atari 800 (mid to late 80s) had chaff for countering radar-guided missiles and flares for heatseekers.  IIRC, you could tell the difference by the lock-on tones.

[AdmiralRalwood]

You need to know how FSO organizes ship data. There are ships, and there are ship classes. Every ship has a reference to a ship class. Changing ship class values directly is an obviously non-working idea, since you would be changing the behaviour of every ship of a class in the mission at once.

This is the basic problem. Any reference to a changeable ship class value will have to be checked and code inserted to check the ship's status to evaluate what the class values should be.

Not a modder, am a computer scientist, had an idea for a workaround.  If there's a way to seamlessly swap out one ship for another ship of a different class (I don't know) then it can be done in the manner of a finite state machine.  Want a bomber with 6 torps that gets faster as each one is fired, then you make 6 bomber ship classes that are exact copies except for the speed being tweaked, then put the player or AI bomber pilot in what's technically a ship of a different class each time they fire but looks and feels the same, copying over the ship's state data like speed, direction, damage, ammunition, etc. 

Apologies in advance for speaking about all this from a position of ignorance on the capabilities of the modding tools.

No, that's entirely possible (that's the sort of thing the change-ship-class SEXP is for); the problem is that there is an upper limit to how many total ship classes you can have, and I don't know how close to that limit BP is, but it would probably go over it if they tried to implement this system for every player-flyable bomber.

[Phantom Hoover]

If you wanted this capability in the engine the best way to go about it would probably be to add a list of properties to each individual ship that shadow whatever's in the ship class.

[AdmiralRalwood]

If you wanted this capability in the engine the best way to go about it would probably be to add a list of properties to each individual ship that shadow whatever's in the ship class.

This is bascially done on an ad-hoc basis for every ship-specific override available in FRED (special hitpoints/explosion data, for instance).