I know how damage resistance works.
So the deal is, resistable damage resistance always increases damage by the amount it says on the tin.
So, let's say you do 100 damage, with a 15% resistance debuff, against +0 opponents.
Against an opponent with a 0% resistance to your damage type, you do 115 damage, or 15% more than you'd do if you didn't have the resistance debuff.
Against an opponent with a 50% resistance to your damage type, you lower their resist by 7.5%, to 42.5%. So you do 57.5 damage, or 15% more than you'd do if you didn't have the resistance debuff.
Against an opponent with a 90% resistance to your damage type, you lower their resist by 1.5%, to 88.5%. So you do 11.5 damage, or 15% more than you'd do if you didn't have the resistance debuff.
An unresistable debuff is weirder. In the same situations:
Against an opponent with a 0% resistance to your damage type, you do 115 damage, or 15% more than you'd do if your didn't have the resistance debuff.
Against an opponent with a 50% resistance to your damage type, you lower their resistance by 15%, to 35%. So you do 65 damage, or 30% more than you'd do if you didn't have the resistance debuff.
Against an opponent with a 90% resistance to your damage type, you lower their resistance by 15%, to 75%. So you do 25 damage, or 150% more than you'd do if you didn't have the resistance debuff.
Like, I think people get scared by hearing "your resistance debuff drops from 15% to 7.5%," but it's super unclear to me why we would want a character with resistance debuffs to add much more effective DPS against high-resistance opponents as against low-resistance ones. What's the game design goal here? Is the idea that high-resistance characters are like puzzle bosses that demand specific approaches? That doesn't feel like it's an element of CoH design. Is it just a general sense that high resistances are overly powerful against a few characters (like lethal and psi-oriented characters)? I think there's a plan of record to make a big change to enemy resistances and try to make them a little more sensical, and that sounds like the right response to that problem, not give out a bunch of unresistable resistance debuffs.
That's a surprising assertion to me. Is Achilles' Heel really unresistable?