FFXI's leveling is very bottom-heavy (meaning, slow to start, but gets fast near the end) now that EXP parties start at level 75-ish.
My brother just joined the game, and soloing/duoing with him is enjoyable, but I think to myself, this would be tortuously slow if not for Double EXP.
Players these days don't have the patience, and with minimal interaction with other players at the low levels, the EXP gain really needs to be doubled so that new players can get into the more popular content and zones faster.
FoV and GoV experience bonuses should also be doubled (or at least FoV). When Page 3 in Valkurm Dunes gives 550 EXP, it's really not worth focusing on snippers and flies, considering one or two monsters give more than the page completion does.
Experience points should also be added to old quests and/or missions. So much of the new content has this, but almost none of the old content has it, when it's low-level content that needs it most.
Finally, the absurd jump in EXP required in the 50s needs to be reduced. It's okay for a big jump to come in the 70s when there's Abyssea content, but when you're in the 50s, soloing is extremely slow, and you suddenly need a ton more EXP per level. Being told, "Now that you're level 50, Abyssea leeching is your only option," is a major turn-off to many people, especially if they're leveling their first ever job in FFXI.
In summary, expedite the journey from levels 1-75 so that players can enjoy endgame content and player interaction sooner, and so that at level 50, players with some pride can keep that pride and earn their levels fairly.