Guild Wars 2

Defiant makes all CC-based weapons unviable for PvE so here is an idea.

Use CC -> Works, but gives boss 4 stacks of defiant.
1st stack reduces next CC duration by 100%
2nd stack reduces next CC duration by 75%
3rd stack reduces next CC duration by 50%
4th stack reduces next CC duration by 25%

This way CC weapons will have a point, but without making the encounter much easier.

What’s the duration of a pull ?

I agree that the current defiant system breaks certain builds (interrupt mesmers), but your suggestion is lacking.
But well, it’s PvE … so “noone” cares.