The core issue i have with leveling currently is how progression through the cities is currently handled, it has nothing to do with how much EXP i get or anything like that. Currently as you progress you normally run into two road blocks in progression the first is the level requirement to enter a new zone and the level requirement for the 3rd and sometimes 4th episode within the zone. The second level requirements is where i feel like the progression is ruined and is one of my main reasons for hating the leveling process so much, it forces you to leave a zone and farm episode 4 of the previous one.
My suggestion is to make it so the only level requirement needed is the one to enter the zone and remove any other episode level requirements. This would make progression feel so much better and make it so that the only episode 4 you would ever have to farm would be the most current one instead of a previous one. This change should probably be considered a QoL change considering the episode 3/4 level requirements are just arbitrary and serve no real purpose other then barring progression , its not like being one level lower will suddenly make the episode impossible finish. This also does not effect difficulty of leveling or anything else really since you will still need to level to enter the next zone.
Currently it looks like this in most zones:
Episode 1 - level requirement
Episode 2 - no level requirement
Episode 3 - level requirement
Episode 4 - level requirement (Sometimes)
My suggestion:
Episode 1 - level requirement
Episode 2 - no level requirement
Episode 3 - no level requirement
Episode 4- no level requirement