Some penances just don’t make sense because either (1) your team sabotages you or (2) you sabotage your team.
Example of (1): Preacher needs to stun AND kill 50 targets in 10 seconds. How the heck are you supposed to both stun 50 targets with a grenade and kill them before your teammates kill the stunned, squishy enemies? You need to wait for weapon swap too.
Example of (2): Malleus Monstronum. Actually this one is both 1 AND 2. How the heck do you want a team to just not contribute to a boss?
+1
There’s a lot of Penance Quests that are counter to working as a team. It’s something I really hope Fat Shark addresses before release. 
I’ve been having such a blast in Darktide, but the absolutely insanely aggravating Cliffhanger penance is seriously ruining my time. Please guys, this is infuriating.
Some of the penances and contract requirements really wreck the game. I think the game would be better with this content omitted, or switch all of them to just achievements.
Wholeheartedly agree! It goes against the fundamental design goals of the game to have penances like “solo a monstrosity with brain burst”. The only thing these penances promote is sitting and waiting for the right mission on the right difficulty to pop up and quitting early.