Implement some sort of 'Diminishing Returns' mechanic

Ok, so, I am enjoying myself in the game for the most part, but one thing that REALLY annoys me to no end is getting chain stunned or chain slowed until you're dead, and you can't to just about anything against (Ex. ...all of her, getting stunned multiple times in succession). So, I suggest implementing a Diminishing Return mechanic, wherein slows/stuns are used so many times on a single target that they are eventually useless for about 3-5 seconds. Not sure if it's got suggested before but I feel like it would make things less frustrating and a little more strategic, in a way.