Grinding on a new never before seen map doesn't count as new?
I mean, if you really think about it. That's all Hunts ever were, is FATEs without a FATE indicator. I don't see that ever changing no matter what content we do. The difference in this situation for the relic grind is that SE had the option to make us grind SB FATEs or give us an instance instead. I'm grateful for Eureka over SB FATEs because now I can do FATEs cross world instead of alone on a lesser populated server.
I hate to break it to you, but PotD is just as shallow and recycled as much as any other content. PotD much like chaining mobs inside Eureka is just kill the same monster over and over for 10 straight floors. Even the scenery is more repetitive than Eureka's. The music? That cycles between basically a youtube playlist of songs. At least Eureka has it's own consistent track. The pomanders don't really add much to change the experience when most of the pomanders get saved for the last floor or two and the boss fight on the final floor. The difference that makes many players enjoy potd more is that they are physically capable to run off and solo on their own and survive if they wanted to, unlike Eureka. Which in turn makes it easier for them to go at their own pace. In addition, it also appeals to levelers because it's the fastest way to level in the game. Doesn't mean it's the funnest way to level. If Eureka gave leveling exp form the FATEs to your job classes, I think players would quickly change their minds about how much they dislike it.
If you remember, PvP was more or less dead outside the hardcore players until they added exp to it. It's pretty clear to me that offering leveling exp is the biggest incentive this game can use to motivate players to do content. But that comes with a price. Add exp as a reward and that'll attract the bots to the grind.
Lastly, sure PotD let's you try out other jobs, I'll give it that. What it does not do is give you real situations to actually learn your rotations for those jobs. When everything dies in 3 hits, you won't figure out much for that job you're trying besides the basic combo and what some of the buffs are. SE could easily fix this by providing an instance based SSS dummy that let's players queue solo at level 1, and provide access to all of the job's skills when inside.