In FFXIV, a player can unlock every available job on one character. That being said, once every job has been leveled to the max, 'that's it'.

I'd like to suggest a system to level a job all over again. Allow me to list a few benefits:
  • It'll be an evergreen system
  • The system will be completely optional
  • Players engaging in New Job+ will run (lower level) duties, this helps newcomers and roulette players
  • New Job+ players may make use the market board for materials and/or gear pieces, stimulating the in-game economy
  • Tomestones of Poetics will have a use again for players who have long since had no use for them
  • Players won't be forced to make an alt character to level jobs again
  • This system should not affect available level boosts for jobs. These will remain a viable option for players who wish to make use of them
For this system, I wish to voice several wishes and solutions for practical elements:
  • Just like New Game+, this system should have a 'pause' option
  • Once New Job+' progress matches the maximum level of that job, it'll conclude
  • New Job+ could unlock at L50 for ARR and HW jobs. For jobs added in Stormblood and later, New Job+ could unlock when completing their job quest chains
  • Job quests should be part of New Job+. They should not give material rewards, but unlocking abilities should remain a part of job quests
  • Role quests should be part of New Job+. Material rewards are not necessary, but they could still serve to unlock job 'artifact gear' at the relevant NPC's
  • For ARR jobs, resetting the relevant Hunting Log entries would be a nice
  • Being able to select a 'start level' is recommended, such as: level 1, 30, 50, 60, 70(, soon 80)
  • Some jobs start at a higher level, such as 30, 50, 60 and 70. I recommend using the stat scaling system that exists on Earrings such as Menphina's Earring and apply it to the current 'starter' weapons for these jobs. They would scale up to their original level requirement, since upgrades will become available from that point on
  • FATEs, dungeons, guildhests, trials, raids and deep dungeons should be accessible with New Job+. Field Operations could be included.
  • Providing armour pieces when starting New Job+ is optional, but I believe that players can source those easily enough. I'd advice against using a stat scaling system for armour pieces
Let me know if I missed anything!

I personally love gearing up and leveling my classes and jobs in games. I fully acknowledge that not everyone is of the same mind. I hope that the points I've made will help convey that there are only benefits regardless of which side of the fence you're on <3