Based on reading latest patch notes, I could not help but notice that it seems to be "feelings" based.
"We've rolled the control effect into the skill itself and increased its casting time to ensure that it feels reasonable. "
"Finally, we're changing the mirage's Elusive Mind trait to no longer break stuns as we **feel ** that the necessity of including exhaustion as a balancing factor has made it too binary as a choice."
"In exchange, we've added a few new powerful traits with drawbacks as we **feel **this is in line with the spirit of Mallyx and skills like Pain Absorption."
This made me curious and tried to look to the previous balance patches to attempt to determine what is considered 'fair' for devs; that is, what is the basis for nerfing or buffing a particular skill. Don't get me wrong; I'm not saying they're misguided how to buff/nerf skills, but I wish devs would share what their guidelines are for buffing / nerfing skills during balance patch notes.