I think it would be fun if a feature was added where you have to eat so much food per 24 real time hours... All of these ideas could be changed depending on popularity.
When the game starts you are taken through Culinarian to level 5 where you learn to make a basic dish.
This dish enables you to replenish the hunger bar on your UI.
The hunger bar drops from 100% to 0% over a 24 hour period. When it hits 0% you are unable to fight/gather/fish. You can however still cook but only the special recipe or buy it from market place.
Once your hunger bar is above 0% you are able to continue as normal.
To eat this special meal you will need certain equipment.
Armorer = Plates
Blacksmith = Cutlery
Goldsmith = Goblet
Leatherworker = leather bag to put Cutlery and salt and pepper shakers/grinders in
Weaver = a Picnic basket
Carpenter = Picnic Table with built in chairs.
Alchemist = Special additives that add enhancements that last 24 hours.
Culinarian = The Meal.
Fisher = Fish for meal
Botanist = Fruit & veg etc for meal
Miner = Metals for plates, cutlery, goblet and salt & pepper grinders/shakers.
Bear in mind this is a rough idea and every thing can be expanded on.
Every 10 levels there will be a new culinarian recipe which will fill up your hunger bar to maximum.
The previous recipes can still eaten but will fill you up less.
Each meal can be made with special additives that can add extra stats boost or other effects that last for 24 hours.
Other effects could include..
25% faster fun on foot.
25% faster Chocobo.
Every time you die you have a pop up box that allows you to resurrect with low HP/MP.
Normal speed while under invisible effects from disciple of the land jobs.
More HQ items from dol & doh.
Make you look like various mobs in the world or different Races.
The items needed to eat the meal with could come in various designs/looks.