Right now you can do two things to level up in this game when you have done most of the main story and all quests, you can do FATEs or you can do dungeons because they give you viable amount of experience points.

I would like to se a great boost in both mob farming experience and a little bit in guild leve experience to make it more viable, I mean you can do 3 leves every 12th hour and you gain 6763 exp per leve at level 40, that is 20289 exp without the difficulty and speed clear bonus, its far too little experience gain every 12th hour when you need 356800 to gain a level at level 42.

And you gain about 350 exp per mob when you chocobo is not out, that number is far to low and even if it gave you 1000 exp per mob you would still need to slay 367 mobs to gain a level and that's more of a viable target to exp gain in my opinion.