As much as I abhor the world quests in WoW on the long run [for different reasons], they got the right idea by placing different rewards to incentivize players into doing them, not just marginal XP and a secondary currency. I do FATEs because immersion mostly, and most are rather fun, but objectively speaking, they're generally a waste of time.
It'd be nice if FATEs gave loot, currency, reputation, or even tomes depending on the type of FATE it is, the region it's in, and/or the factions involved.