Honestly, I agree with pretty much everything you’ve stated.
The only real counter is something like “get good” or “play the meta then!”
That’s not fun or helping you progress on a character you have.
There’s already an NPC that will deplete your key if you so choose inside of Valdrakken (future cities included)
There really is no benefit to depleting a key, even the few benefits of risk/reward don’t make sense if you truly look at them.
However, every con you’ve put out is absolutely true. There’s a weird list of items that can deplete a key and only two of those are skill and uniformity of a group. Everything else is out of the player’s hands. On top of that, for some reason people love rage quitting now.
Tanks that get upset you have Dynamic Targeting on and accidentally cast/shoot something so they get upset you’re pulling for them, then they either leave as soon as that happens or shortly thereafter.
Sometimes you encounter a healer that can’t keep up with the healing required, regardless of what their IO says about them, or what progress they have on that character and it’s just a smart move to leave so you won’t waste time.
Sometimes there’s a DPS that’s just not pulling enough for unknown reasons so people just leave.
Regardless those are a skill issues, and people get annoyed and leave.
The real problems begin with disconnecting; not being able to play what class you want; not being creative or being able to learn at a higher difficulty.
For example,
You have someone disconnect and you guys keep trying to progress but after 5min, the DPS doesn’t comeback. - Depleted
or
It is the Tank/Healer that disconnect, you wait for 5min and everyone leaves. - Depleted
You try to join keys that are rank +6 to +9 (not even +10) and people may not invite you purely based on your class. - Didn’t even get to try
or
You do your own key and get it to where you need it, but it’s not a dungeon you need. Now you HAVE to try and join other dungeons of the same or higher level in order to change your own key from the NPC at the end of the M+. - Didn’t even get to try what you needed to run
With the new system for M+ and the difficulty of everything increasing so that a +10 is equal to what a +20 was there’s a larger gap in difficulty between keys.
If you’re in a group with friends, you can mess up as many times as you want until it’s called or you clear it. - pushed forward and forced, through social contract, everyone through it.
or
You attempt to try certain pulls differently because you can’t quite gauge how you should pull at this point, however you won’t complete the key. - Depleted for learning
or
You learn how to pull get the key back up but due to a mistake in your rotation or CDs you die and cause a wipe. Everyone leaves - Depleted
For what? Who does this benefit?
It’s certainly not Blizzard, it’s not the key holder… no one benefits.
I agree if you don’t time the key your only reward should be the Vault reward next week.
If it’s too much you just go to the current Major City and request a Key Depletion.