The biggest issue with M+ is leavers. Sometimes they leave because they screw up or don’t understand mechanics. Sometimes they leave because they are very entitled and selfish. Either way it sucks for the other four players and especially the key host.
So what if Blizzard implemented a one time per dungeon “pause” and recover. Much like Raids you don’t have to stick with a bad egg or lose all your effort because of them.
The M+ would pause and you would freeze within the instance, giving you a chance to re-open the party and replace the lost role.
Clearly there would have to be some refinement with the general idea and of course a limit to how far in progression the dungeon could be “recovered/saved” since there could be carry exploits and maybe only a one time thing.
But I think this or something along the lines of this thinking needs to be put into consideration because M+, as is, is a very very bad experience for the average player.