The simple solution is to make joining another M+ have a 1 hour timer if abandoned. 2 abandoned in 24 hours equals 2 hours for second offense. 3 abandoned in 24 hours equals 3 hours for third offense. After that locked out from Mythic+ for the day.
This would 100% not punish those who leave too severely, but would make them a tad more courteous. The person who leaves wastes much more time than one hour when factoring in a group of 5 people.
Edit: Dumb idea 
More cons than pros
Ya no, that’s a horrible idea that will be abused.
How exactly will that be abused? The 4 that are in the group get no time added and can replace whoever left and run the key -1
No thanks, if you’re bad people deserve to leave your key.
If someone is feeling pressured to leave, 99% there’s a deeper issue.
I don’t agree with that person being punished when a group goes south.
1 hour lockout is hardly a punishment unless the act is habitual.
Besides people making groups just to grief others with the debuff?
How about group leads kicking people before the final boss dies?
What about people making groups with the aim to get carried to realize they won’t time the key and kick people?
What about joining a key where the others clearly don’t possess the skill level to finish?
What about a group where the people do nothing but harass someone until they leave?
There are numerous situations where this can and will be abused, I only listed a quick few that came to mind.
good lord people.
the simple solution to m+ leavers is not pugging.
anything other than that is easily abusable, and doesn’t take into account why people leave.
The biggest issue with this is that people will just AFK instead of leaving, and that will be a bigger problem
But what about the people pushing super high keys that fail them all the time and don’t finish them cause it’s literally only for rating?
Ideas similar to yours have been discussed to death on forums. For example, someone can abuse it by not leaving and just going afk. Eventually, someone else will leave first and the actual perpetuator doesn’t get punished since he was not the “leaver”.
Also, there are many people who have already filled up the vault and push high keys for fun and IO. For such groups, it is generally accepted that people will probably leave once there is no chance to time the key since they have little incentive to finish.
Yeah, it’s pretty simple. I’ll just not abandon and go exploring the dungeon where we cleared trash, looking at the textures and art and get loss in the scenery, until you just decide to take the punishment yourself because you’re tired of waiting for me to walk back to the group.
If you act up in chat, I’ll dress you down about all the mistakes you made. And if you get really toxic, I’ll “speed up” the key by pulling so much trash you keep chain wiping and I’ll kite it to the respawn point and keep it in combat.
Simple often means ill-thought out. Punishing leavers only means leavers will figure out how to make you leave.
What even constitutes leaving anyway ?
Do I need to drop group ? Because it’s a 5 man, I can just hearth and go do mog runs too.
Did you forget to swap to a sock puppet before agreeing with yourself there champ ?
EDIT : and now he realises and deletes the post. This thread is going places.
Absolutely not.
The best solution I think I’ve seen on these forums is to give a couple of charges to a key as bad luck protection, but that’s about it.
LOL
New to this forum, misquoted several times now clicking reply to wrong person.
Is to play better and invite better players.
People don’t leave good groups.
It sounds like you have a lot of experience.
Sure. Instead of editing, you went right to delete.
The solution is simple: ban anyone making these threads.