I love class/job ideas, and I think dancer would be nice; however, here are some things I wanted to share my views on.
Weapon: Greaves
Why would they wear heavy armor, or anything that would hinder their dancing, it doesn't seem like a reasonable weapon for them. Honestly as many other concepts have suggested I would prefer dual tessens as their weapon of choice it would just fit them so well, and SE hasn't added an eastern type dancer to the series as of yet, that type of aesthetic would be awesome. Maybe when we go to Doma they can release an eastern based expansion with the following jobs. Also a lot of people are putting their money that Samurai would be released in the next expansion; however, in my opinion it would be better to add Red Mage next, and Samurai afterward since they are the most requested jobs and they will sell expansions.
A.) Dancer (Healer) / B.) Shogun (Tank) / C.) Samurai (DPS)
Jive
Why does it have elemental damage? elemental affinities have nothing to do with Dancer, and it's not like there is any elemental weakness in this game, it could be a magical non-elemental attack.
Curing Waltz
Why does it have such a low potency? there is no reason for any base cure to have a potency of less than 400 since that is standard for all healers. This doesn't have an additional effect such as a (HOT) or anything to warrant such a low potency.
Mystic Waltz
While I can see this being the job divine seal I just feel it's unnecessary to have it work on the party members when a self-buff divine seal would be easier to program and it would serve the same purpose of raising the power of your heals. Also what is the point of this being level 4? the class needs more DPS to get to level 15 not so much support when nobody is going to be partying with them. Also a cure potency of 90? what exactly is this a divine seal, a regen either way its really underpowered as either of those effects since regen is a potency of 150, and divine seal is a flat 30% increase.
Quickstep
Where's the damage? really the dancer needs more damage also what type of healer do you want them to be? a "melee healer" a "healing overtime" healer, etc.?
Dirty Dancing
Why is this much weaker than aero it has lower damage, and a lower duration.
Divine Waltz
Why does it have a 50% nerf from Medica is this job so truly overpowered that it requires a 50% less efficient AOE heal.
Drain Samba
Instead of making it an annoying recast every minute with a duration of (15s) it could be a stance where your dancing while attacking the enemy. it'll make it a less annoying utility and give you a reason to be in Melee range assuming you want DNC to be a melee healer.
Curing Waltz II
So you're giving them such a weak cure at level 2 even weaker than Eos, but at level 22 even before WHM gets cure II you're giving them the strongest cure? it doesn't follow; also a potency of 950 what is the recast of mystic waltz if its less than a minute that is overpowered.
Slow Dance
This looks like a level 1 ability, and in addition heavy is such a weak additional effect why not actually give them slow.
Aspir Samba
Same response as Draining Samba.
MP Mambo
It's a unique effect it could be their SoS; however I would increase duration to 15s.
Polka
I can see this as their "virus" spell; however, they really do need damaging spells even a White Mage does more damage than them lol.
Chocobo Jig
Overpowered they are able to provide the same two supports of BRD at the same time, as well as a haste on a 2min recast.
Jive II
Finally a damaging spell but I'm also noticing that almost none of your damage spells have additional effects.
Magical Masque
Super overpowered, maybe if it was one hit on a 10s duration.
Divine Waltz II
Same potency as Divine Waltz??? and also OP for an additional effect since you'll basically want to recast it everytime it wears off. So in your concept you'll have a 15% buff for every minute (20s) due to Magical Masque.
Heathan Frolic
Elemental Resistance doesn't exist in this game, you can have it provide buffs to certain elements but not every element is really used ingame such as water, air, and thunder is limited.
Chaotic Jive
Huh? this is an AOE? also as before element affinities are pointless that's just aesthetics.
Miracle Waltz
it has a weaker potency than Curing Waltz II, and your effect of Mystic Waltz would raise it to a cure potency of 1200 its uber overpowered for an enhancement that you have on you for 30s. its a basically a 30s benediction
Carnival Cancan
This dance favors warriors, it needs to also be favorable for DRK/PLD.
Spectral Dance
So Spectral Dance and Mystic Waltz would make you the best healer in the world? Balance is very important nothing should be able to outbeat a WHM in raw healing power.
Freestyle
lol a potency of 300 and reapplying Mystic Waltz just no, now they are the best DPS healer and the best healer lmao. heck they might be better than some DPS jobs.
Dirty Dancing II
Double strength of Aero II, yet the first one was weaker they need to have similar properties either they are stronger than the aero line or weaker.
Contradance
Mystic Waltz, Freestyle, Contradance just how much power does DNC need? its unnecessary for 3 enhancers that increase potency.
Chaotic Jive II
As C.Jive I need more info is this an AOE, is it like that wave attack monks have from WOW? if its a AOE its OP.