As written in the 14.6 Changelog:
- The 14.6.0 fix resolves issues where Rage + Quick Thinking gave effective permanent invulnerability because energy was being added to pool that was never dealt to player. With this change in mind, the combination of Rage and Quick Thinking may seem less efficient as before due to no longer giving effective invulnerability. The scope of this change is being monitored to ensure the usefulness of these Mods as a combination.
Basically they wanted to change this combination from "PRETTY FUCKING OP" to "nice". But like always such changes just break a mechanic. I just tested its "Usefulness" on Mercury, after getting to the infamous 2HP mark a lvl4 Butcher was able to kill me in 4 hits( i have a 202 energy pool), which basically means, that this mod combination isn't even useful at the very beginning of the game.
Even DE thinks that Rage + Quick Thinking should mean something to the community, but nerfing it in such a way isnt the right choice. This combo has always meant to be something like a godmode, but if you nerf god, whats left of it? Just increasing the efficiency of the combination also wouldnt be a good solution, because it wouldn't scale into lategame (and btw, those are some lategame mods). So why shouldn't DE just completely change the Mechanics on this Combo? They could actually make something like "after your health dropps below 3HP your energy gets drained and you gain 1second of damage immunity for every (x) Energy you had" instead of "balancing" it out.