It's been a while now since there was a major overhaul of the Mistlock Instabilities, and although we did get the (much needed) removal of Birds and Slippery Slope, there are still a number of Instabilities that don't feel like they meet the goals that Anet set out to meet with the rework. In addition to this, there are a few that desperately need QoL adjustments:
Flux Bomb - I personally think FB is a decent instability, but it shouldn't be applied at the very start of combat. For many bosses, the first few seconds of the fight are crucial both to CC the boss, and to capitalise upon the damage buff from breaking it. The appearence of Flux Bomb frequently amounts to simply blocking one player from actually contributing while they deal with the instability and for many encounters there just isn't any counterplay to this. An example of this is Ensolyss - A skilled group can instantly break the boss, but the time it takes for the defiance bar to appear coincides with the Bomb, which leads to effectively needing to "reroll" the start of the fight in the hopes that it is given to a class who can CC while dealing with the Bomb. Alternatively the group can simply abandon attempting the instant break, which amounts to removing skilled play from the game.
Frailty - It's bad enough that this instability effectively just amounts to "take more damage" with no counterplay, but the positive effect is useless as it does not stack with the swiftness that most groups will have anyway! Honestly I feel like this instability should just be removed, as it is uninteresting and plain horrible when combined with the other "take more damage" instabilities.
Social Awkwardness - This should really only be active in combat, as it is incredibly frustrating to have everyone jostling for position around the many awkwardly placed Mistlock Singularities.
Sugar Rush - More interesting than Frailty, and as with that instability the positive effect does not stack with the boons that most groups will already have. Perhaps having the instability apply quickness rather than a generic attack speed boost would work better.
We Bleed Fire - The "boss" version of this Instability was not updated along with the base version. Hence it still does not reflect, and applies the very long duration burning.
I don't by any means think that my suggestions are absolutely the best way to fix these instabilities, but I do believe all 5 of these need a rework of some kind. I've tried to focus more on the instabilites that create systemic issues based on my experiences, rather than just my personal opinions so I'm interested to see people's thoughts!