This is a small list of changes that feel appropriate to keep up with faster clearing teams (excluding Mutation). I do not feel that anything here is truly game changing, more of just removing tedium.
Radiation Infection - Allow players to affix it to other players (e.g., tank) (thanks Luminara), reduce cooldown to 1 second, -or- (if possible) allow target swapping without triggering cooldown[1].
Enervating Field - Allow players to affix it to other players (e.g., tank) (thanks Luminara), reduce cooldown to 1 second, -or- (if possible) allow target swapping without triggering cooldown[1].
Mutation - Could this be altered to function loosely similar to Phoenix Rising? "Similar" in the sense of being able to use it against a non-dead target, with greater potency with lower health on activation (max effect when used against dead ally). It should still be targetable, unlike Phoenix Rising, to fit with the Controller/Defender/Dominator role.
Choking Cloud - Reduce cooldown to 1 second as it feels like a situational toggle. Having a 20 second base cooldown feels just bonkers. (thanks Uun)
If there is something unknown to me, such as the ability to potentially abuse cooldowns and stack multiples via a single character: please let me know! I might be overlooking or simply not knowing of current caveats or shenanigans.
[1] - I am using target swapping here to mean the effect is currently active on one target, then selecting and activating on another target to effectively "move" the effect without toggle off->wait->toggle on. This would only function if the effect is still active when attempting to "activate" it on another target.
EDIT 20240330: Thanks Luminara and Uun for the valid points!