Please make it happen!!
A 50 floors dungeon, where you need your chocobo (and maybe another player+his/hers chocobo).
On 1F, every enemy is level 1, and on 50F enemy lvl is 50. Floors are not very big.
Only the chocobo gain experience, and it's a lot more exp than you'd get fighting regular enemies, which is the only way now to level chocobos and it takes AGES!
You'd still have to run all floors a few good times to level your chocobo fully.
You can change your character's job/class between floors.
You can (re)start the dungeon at floors 10, 20, 30, 40, and 50.
At every floor you get some loot, like (1) chocobo paints (or special chocobo food that dyes its feathers after a while or after being fed n times), (2) new bardings, (3) special items that reset the skill points already allocated on TANK/DPS/HEAL chocobo ranks, and (4) Chobobo/Mog/WHM/BLM/Goblin/Golem/... minions based on PS1 Chocobo's Dungeon/Chocobo Racing games.