Most of us have been 50 for quite a while, and when doing some of the older content, like beast tribe quests or some levequests, it seems like the xp is getting wasted. I think it would be awesome if you could build up individual points, like FC points as you get XP, and then use that XP for similar buffs to yourself, the same way you do with FC buffs. You build up IP (individual points) and then can spend some of it on a 5% exp bonus for fighting / crafting / chocobo xp / retainer xp bonus / spirit bond increase / crafting bonuses / gathering bonuses / reduced teleport costs. If you wanted to limit it, you could say that a similar FC buff and a IP buff don't stack, that only one would work, similar to how you can't have both tiers. That way if your FC wanted to spend their FC buffs on spirit bond increase, but you wanted to level one of your gathering classes, you could use your IP the bonuses that you want.