There's always Kojin Tribe quests to kill time while waiting for duty. I totally prefer that and sometimes a FATE with Exp bonus than doing PotD. Frontline Roulette and Alliance Roulette gives a lot of experience too (don't know in numbers but those are the methods I use to lvl up from 60 to 61, or if I feel like lazy leveling, to 65 and then spam the last 3 dungeons). Even in the case PotD would give good experience, is just a big no for me ;(