Guild Wars 2

When I remember correctly, the patch with which Defiant was introduced said something like: Defiance is a temporary solution, so that Bosses and content does not get trivilized by perma stuns from groups.

That was around 3 weeks after release.

The problem with defiance is well known, as pretty much all control setups are useless against Bosses and one reason for DPS + boons all the way as the only strategy. The alternative of having no DR system for CC is also bad, hence why we got defiant in the first place.

Here is what I would suggest to do with Defiance:

Resistent
After a Boss gets hit by a CC skill, he gains Resistant, making the next CC skill 50% shorter. This lasts for 3 seconds after the CC is gone while being completely resistant to another CC in that time. This buff only triggers if the Boss is actually effected by the CC (i.e. has stability and gets feared = no Resistant).

Defiant
If the Boss gets hit by a CC skill while under the effect of Resistant, he gets the Defiant buff, making all CC skills completely ineffective for 5 seconds after the CC ends, while being immune to other CC while under the effect of another CC. This buff only triggers if the Boss is actually effected by the CC.

If a Boss gets hit by a CC skill while under the effect of Defiant, the skill is ineffective and Defiant is set back to its full duration. This buff only triggers if the Boss is actually effected by the CC.

Pro:
This change will make Bosses controllable in small, organized groups. In open world events people will spam a lot of CC anyway and the Boss will not become more trivilized by bigger numbers as he will be Defiant all the time. As fights become more difficult the less player are fighting, this change would accomadate this well.
A timed system will make coordination a lot easier than the current stack system.

Con:
Some Boss encounters might have scripting problems if often CC’ed, or still become trivilized due to common interrupting of key skills. Therefore Bosses should also have condition cleanse or stunbreakers on their key skills, especially on the skills that are needed for scripted combat. For example, Tequatl should have stunbreak/conditioncleanse on some of his skills, while also being unshakable as a big dragon. Another alternative would be to script some skills uninterrupbtable and they will just be delayed and casted right again after CC is over.

The same system could work for players, but defiance should be scaled up from 0% to 25% effectivity.

The system could also work with smaller iterating numbers from 0-100% increasing by 1% every 0,01 second. When CC’d the reduction will be set back by 50% to a maximum of -100% (Still 0% on the screen but no CC for 10 seconds). But this will lead to problems with animations that are longer then the CC as why I have chosen 50% and 0% as limits. Seconds etc. are just guesses and need testing ofc.

Diminishing returns sounds good. But that con is likely a big one, would likely require making bosses cast a lot more often.