Generally, blizzard does not enforce penalties for leaving if they (meaning blizzard) did not “make” the group.
By making I mean in queued modes. If they groups are formed by random players chosen by blizzard, they try to provide a reason to stay in said groups. This works for queued content that is either:
- Pretty easy
- Designed to have a 50% win rate (pvp)
Only reason they have acted on leavers for m+, is in cases where there is actively trolling involved (like people joining a key just in order to leave and ruin it).
It might seem like a punishment from the player’s perspective, but also acts as a “force” to provide lower keys for players to play. If no depletions were in the game, then everyone would be “clumped” in the +10 range, and new players or alts that wanted to do a +4, +7 or +9 key would have almost no one to play.
Just to be clear, those reasons are blizzard’s thinking. I do not fully agree with them 100%, but I understand why they are in place at the moment. Of course there are improvements that can be made, but I do not think deleting key depletion or introducing a penalty for leavers would help.
In a social ecosystem in m+ pugging, such system would either be:
- Gamed around (like not leaving but faking dc/ruining the key), thus making the experience either the same or worse.
- Have negative consequences like ruining the balance between people wanting to make groups and wanting to join groups. There is a balance you want to have between wanting to keep one’s key vs entering someone’s else key.
From my PoV those issues are better addressed either by:
- Opt in systems. Like introducing a leaver debuff ONLY for groups that have opted in as “completion”, so that they do not impact people that want nothing to do with them.
- Provide more INCENTIVES to complete keys vs leaving them. Generally punishment in games is way more negative than incentivization through rewards. Lower crests is one example that there is no need for it to be in the game.