Simple: Too many things can go wrong with it.
Say you’re the odd man out - a random. You’re skilled, but you join another group, maybe a trio, maybe another random and you join up with a duo. The duo or trio already has a flow; they instinctively understand how the others play and know their roles. You’re the outlier. You go down more because you’re not used to their rhythm. You’re still skilled. When you’re with your regulars, almost none of you go down. But now, these randos you’ve joined stay up - you’re the one dropping.
So what does that mean? Are they carrying you? No. You’re just as skilled. You’ve proven that with your regulars. This group just doesn’t mesh with you.
I’ll admit, it’s not always like that. Sometimes you’re just off. Havocs are way harder than Auric Maelstroms. There’s no real “warm-up” for that level of difficulty. And if you’re having a bad day, you can’t just quit - not with the current strike system.
The proposed system removes penalties for quitting, but there’s no way to join a mission in progress. So if someone leaves, you could avoid punishing those who stayed and punished the one who quit. This would also leave room for someone to “take one for the team.” How do you design around that without punishing the people who stayed?
There’s also tactical downs, where if you’re short on ammo, or you’ve got too many wounds and you know the group can clear the next room, take a tactical down to reset your wounds and ammo.
There’s more issues: if a strike requires multiple downs and the whole team wipes, one player’s mistake causes everyone to get one down. No harm no foul for one down, right?
If you’re running with randos, trolling and toxicity become real risks. How do you design around that?
This system also rewards stealth gameplay as all you have to do is hit your combat ability and put all of your aggro on someone else for them to deal with the bite you chouldn’t chew while they’re also dealing with what’s on their plate.
What is being suggested, with strikes on downs, sounds good on paper. Strikes based on downs are far less stable in design than the current system - and far too complicated. There’s too many ways to cheat and abuse the system.