I am all for challenging things. 20 consecutive headshots? sure thing. Knock down 70 enemies? Heck yeah.
Let us look at what we even get for completing these, Cosmetics. Things we do no see in mission, only see on the ship and (admittedly) sort of status symbols. The point values for Penances do not seem to connect to anything, and it has been admitted that it is just for funsies. Some of us like the challenge of completing these achievements so the grind of material and currency farming is less frustrating. Then, when we have accomplished the achievement it feels good to have a sense of being “done” with the challenges.
So the question becomes, why are some of them so absurdly out of reach without putting 3 other players in danger, boredom, frustration etc… ? It doesn’t feel good, especially when MANY (not all 
) seemed to have accomplished these when there were exploits and shortcuts.
Make every Shot Count - I have lost count of how many times my friends have tried to help with this, but getting hit by a mob no one noticed, someone dodging, input lag or something make that one shot hit armor or miss. They are tired of trying, and so am I… Now it just gives me a sour taste.
Just a flesh Wound - You made the layout of missions longer. Added checkpoint doors that now require the dawdling player to be with me to move on. Where we could finish this on pretty much any heresy+ mission with good play, it has become another source of contention. I ran a hab dreyko on lvl 1 just to see what the pace had to be. We still hit 21 minutes. Is it “possible”? Maybe, but is it realistically attainable by most people? Not really. So many factors can make the ‘perfect’ run into a bogged down mess.
On the flip side of this, Ogryn penances became easier with the new layouts and now the new mission special conditions. Psyker have as well. heck, there is a mode that spawns 5 targets for you at regular intervals… you will get it eventually and it is just good play to do so. Accuracy and speed are “good play” but not missing a shot with well over 100 shots? Even with the lowest ammo capacity weapons, our innate ammo regen skill will keep tossing us rounds. People say the excess shots do not need to be taken but … Is that good play? Is that something we should be counting?
TLDR: Please do something to make people a little more happy with the state of things. Ease up on those two Penances at the very least. 21 minutes seems reasonable. Overall 70% accuracy (ignore remaining ammo, how absurd… ) Heck, even 75% 80% if you feel like giving players a cosmetic item is just too valuable.
Thanks for your time.