Which jobs is at its prime?

[Jirah]

BRD (And MCH) went through so many changes it was good or bad to play.
In HW, they added casts. It worked with MCH but not with BRD which was not designed with casts in the first place.
In SB, they removed the casts, which makes BRD to be played like a BRD again. On top of that, BRD had massive utility and really good crit buff to all allies.

In ShB, they removed a lot of utility and never balanced the removal of rDPS.
As for new actions, song doesn't feels like song but more like stance, each of them having their problems.

The job relies massively on procs, so much you could compare it to a WoW class.
Mage's Ballad refresh Bloodletter and Rain of Death cooldowns. But those two cooldowns don't have charges, so you definitely lost some casts.
Army's Paeon is boring and the skill speed is also based on RNG.
The Wanderer's Minuet is the same, based on RNG to use Pitch Perfect and any overflow is lost.
Then you have the soul gauge. It's a bit like MCH wildfire, you cast it around every minutes and just it just empties the gauge, it doesn't feel impactful, doesn't deals incredible damage (It only outclassed Sidewinder in 5.2, will remains the same in 5.3), it doesn't feel as a ultimate skill like NIN's Hyôshô Ranryu, DRG's Life of the Dragon phase or SAM double Midare.

BRD is massively RNG based and RNG can punish you. And on top of that you are the worst DPS, if people lets you in their party, it's for the 1% bonus.
That's the take from a MCH, thought. A main BRD could probably bring better and more relevant points.

I’d argue Dancer is far more RNG based, I’ve had times where I’d do 1-2-1-2-1-2 with luck not being on my side for flourishes. Also “worst dps” is abit hyperbolic considering I know some Meta would rather you MCH for its mindless DPS or DNC for its personal buffs but mastery of the fight outclasses DPS. Also idk if your well versed in BRD to speak about it no offense. (Comparing Soul gage to Wildfire the most redundant skill in MCH arsenal took the cake) and didn’t bring up Army’s Muse or Emperyl Arrow granting Repertoire gives you control like Dancer flourish but less toothless and every 15 seconds.

[Beddict]

I’d argue Dancer is far more RNG based, I’ve had times where I’d do 1-2-1-2-1-2 with luck not being on my side for flourishes.

DNC also has multiple layers of RNG that BRD doesn't have. With BRD you either get the proc or you don't and that's the end of it. With DNC you use Cascade and hope to get the Flourishing Cascade proc, then you use Reverse Cascade and hope to get the Fourfold Feather, and then you use Fan Dance and hope to get the Flourishing Fan Dance proc. That's a lot of RNG baked into the kit.