You have to understand about those types of actions. They were conceived of to give these Melee jobs something to use when they were forced into downtime. Entering HW, DRG originally had Piercing Talon and NIN had Throwing Dagger while MNK had nothing for GCDs to use while out of range. Thus, Form Shift and Chakra. Shoha was tied to Meditate which always existed for downtime during fights, as SAM got Enpi (them not wanting to revisit MNK's unique detriment). RPR likewise gets Harpe, but also gets Harvest Moon just to get something to do when there's no boss.
It doesn't build any special resources because it's not meant to be used as a cooldown. It exists beyond the 2 minute meta, and I think that's fine. Jobs should get situational tools like Harvest Moon, but then they just need the fight design to give them situations, which is where they're sorely lacking. Harvest Moon makes sense if we're playing RPR in a fight that has forced downtime or many opportunities where there's multiple targets. Those aren't the fights they put into the game anymore.
They don't have melee downtime anymore which is why it feels weird, especially now that PT, TD, Enpi and Harpe don't interrupt your combo anymore anyways, so there's even less of a reason for these tools to exist in terms of your bog standard 8 man encounter. Your Harvest Moons are way more fun and useful doing dungeons and FATEs though, like NIN using hide, you get plenty of chances to ready your extra actions.
Harvest Moon feeling bad is a symptom, not a cause. Making it into another Chakra or Shoha would be the predictable boring thing so they'll probably do it, cuz changing their fights to not have a single, giant target would be tougher to do.
