Well, the devs aren´t the ones kicking players for any multitude of (sometimes frivolous) reasons. And even on these very forums it´s quite clear that the playerbase as a whole has only become more toxic towards new players, or for that matter any player that isn´t “you”.
The only real solution with any merit, and its questionable whether it would actually work out as planned, would be for truly fresh accounts to not ever be Auto-grouped with experienced plaers until they have reached levelcap so they can learn together in an environment where you don´t have a wannabe god dictating how to play and rushing them thourgh the dungeon faster than their PC can render the mobs…
Unfortunately, while that would help truly new players, it would do nothing to curb the idiocy that pugging in WoW has devolved to once they reach max level and /or start another toon… 
And if the penalty weren´t there, you get 1:1 OG cataclysm, “I dont like this dungeon, kick me so I can requeue” … which then griefs the group by forcing them to wait another 15 minutes for a new tank, who then pulls the same schtick, andrinse and repet, and before you know it you´ve been sitting in the dungeon for >2 hrs and haven´t killed a single mob.
The punishments are there, and were added one after the other, because people just can´t act like well adjusted adults but incessantly have to look for the next free ride or way to exploit ever system they can.
The only way to really be “fair” about it would be a convoluted dynamic punishment system that punishes you 1:1 with the amount of other player´s time you wasted… YOu leave? Fine… if the remaining 4 have to waitr 15 minutes to refill the grp, you get a 1 hr debuff. If it´s only 2-3 minutes such asw is the case with most frivolous DD kicks, then you get 8-12 minutes debuff.
The system can not work properly without punishment because people as a whole are self-centered bonobos, that´s why the punishments had to be added… originally there was none, then it was 30 mins for leaving before the first boss, then in cata that was extended to kicks because tanks and healers saw a loophole and hated Greim Batol, and it worked for well over a decade, until even more self centered arsehats decided in TWW S! preseason that it would be cool to ruin countless dungeon runs by loeaving after the first boss and requeuing.
Maybe the problem is simply, as much as I dislike quoting Slipknot, that People =
? 