tl;dr
The game is becoming a lot more frantic with the changes to specialist spawns, requiring a lot more kill setup. This means being able to optimize your buffs from any source to kill an enemy faster or potentially even instantly in situations where it would mean dying and losing the mission.
Adjusting the stack mechanics of Fire Frenzy or Headtaker—or any other blessing that builds stacks based on hits or kills—to decay instead of instantaneously fall off all together would help synergize them with core gameplay.
Breakpoints, or the optimization of enabling yourself to kill enemies in one less hit, is an important part of the design of the -tide franchise. This was especially important in Vermintide. Current blessing designs do not synergize well with this for Darktide.
Many blessings feel frustratingly difficult to maintain at the moment and stack decay would vastly improve their consistency.
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As the balance of the game progressively gears itself toward more and more kill setup (due to the changes to specialist spawns especially), I think it would be nice to adjust all stack-based mechanics like Fire Frenzy, Deathspitter—or other blessings based around building stacks through kills or hits—to decay per stack instead of losing them all instantaneously.
Although I see no actual harm in some of them, this wouldn’t affect things like Blaze Away or Cavalcade or Shred—or other stack mechanics that rely on you continuously doing a certain action.
My reasoning is that with the fix to close-ranged blessings, it definitely does feel like a nerf, and overperforming (weird thing to nitpick: “playing too well”) makes it a lot less reliable to upkeep certain blessings at all in situations where I want to try and set up a quick kill on an elite or specialist, or even a boss. So many buffs fall off almost instantaneously to even utilize them effectively or in a lot of situations that could save the mission from failure.
Kill setup is essentially maintaining a maximum throughput of buffs on yourself to maintain your most optimal or efficient kill potential on a particular target or event, such as hordes or a group spawn of specialists.
For example: you want to set up your ogryn’s Ripper Gun to have 5 stacks of Fire Frenzy before you strike a Crusher with the special to utilize Can Opener. This has the most guarantee of virtually instantly killing a Crusher in T5, and rewarding you for setting up the kill.
A lot of this has to do with breakpoints—or a point in which you can kill an enemy in one less hit—as well, which a lot of VT veterans will certainly tell you about.
Although many blessings at their maximum are certainly extremely overkill, being able to utilize their power at all is very difficult in the game’s current setup. I think applying more decaying mechanics to these blessings would tremendously help with consistency.