With the recent reveal of the 3rd myth raid gear, we now have a pretty comprehensive picture of the healer gear for the last 5 expansions. Mostly, and especially recently it has tended toward a long dress and circlet with at best token variety and - entirely anecdotally - increasingly little engagement.
By my count there are 37⅔/49 enormous cloaks and 16/49 circlet hats. Some of the hats have been fairly creative, although the recent trend toward simple circlets is a bit disheartening.
Briefly putting aside all criticism of the healer gameplay, it would be nice to see some more variety and creativity with the endgame gear, drawing inspiration from literally anywhere but "dude in a bathrobe". The world is an oyster yet the design doesn't seem to take any risks. What does it matter if it flops - the gear lasts 8 months and even if it didn't people are just going to glamour the smallest clothes over it anyway. By taking some more risky (not risqué) options perhaps healers might have visibly glamoured trousers or actually use healer-designated shirts for reasons other than flexing. I wouldn't say the immersion argument holds much water here either given the vast array of swimwear and heavy armour specifically for glamouring on any class.
I probably should have put more time into the opening argument, but as a starting point for discussion I don't think it needs to be spectacularly detailed.
Here is my evidence, a list of most relevant hats and shirts with brief description, crafted and dungeon excluded because dungeon gear isn't relevant mostly and I got bored before the former.
ARR:
AR (Undyable):
Royal Circlet/ankle-length coat (silly sleeves, 90 degree open at front)
Scylla's 4 dogs helmet/floor-length robe (very low neckline)
Demon pointy hat/waist-to-ankle-length robe (waist at front)
Tome:Darklight Calf-length hooded robe
Daystar Circlet/ankle-length dress-robe(mostly open at front)
Ironworks Circlet-glasses/knee-length robe
R:
Allagan Circlet/Tunic (thigh, flappy bit to knee)
High Allagan Circlet (big sticky up thing)/Longcoat (ankles, open from thigh at front)
Dreadwyrm Hood/Dress-robe(ankle length, has dragon stuck to back)
HW:
AR (Undyable):
Void ark broad-brimmed hat/floor length robe (open mid thigh at front)
yafaemi pointy hat/jacket-length jacket (small asymmetrical cape at back, sleeves are fairly big)
Diabolic battered top hat/ankle-length coat (open a sliver at the very front)
Tome:
Asuran horny circlet/floor length robe
job gear lmao (Steampunk top hat/pointy hat/hood)/(knee length fluffy coat, waist high at front/floor length dress/floor length dress waist high at front))
Hailstorm circlet + sticky out bit on left/technically floor length coat (open from waist on leftfront, back made of tails so legs visible)
Shire lopsided bemonocled hat/calf-length coat
R: Gordon circlet/floor length dress (armoured torso though)
Midan circlet/skirt-dress (chainmail effect, knee length)
Alexandrian hood/hip-length jacket (now including big metal claws on side)
StormBlood:
AR (Undyable):
Astrologer's glasses/tunic (mid thigh)
Chemist's monocle/apron (shin, open at back from waist)
Mystic's hat (it's just a hat, even the paletteswap caster one has a veil)/coat(bright yellow, floor length, sleeves don't cooperate most of the time and open at front from knees)
Tome:
Ala Mhigan male pattern baldness hat with specifically dyable blindfold/calf-length robe
Lost Allagan knight's helmet/On-average-knee-length coat (sides ankle-length, waist at front, hip at back - back has sort of net thing down to knees though)
Dai's hat (includes miniature dumbell)/floor length robe (very annoying sleeves)
Scaevan mouthmask with optional visor/calf-length coat (open on right leg)
R:
Genji slightly pointy hat with moon on (lalafell can dye it brown and pretend to be a banana with ufiti mount)/floor length armoured robe
Diamond circlet/comfy-looking shin-length coat (annoying sleeves)
Omega egghead helmet + perma visor/on-average thigh-length dress-coat (waist at front, shin at back)
Shabodringers:
AR:
Type 51 tiny hat + optional blindfold/dress thing with puffy shoulders (mid thigh length at front, knee at back)
Type 53 pork pie hat + optional blindfold/Theoretically hip-length jacket with knee-length extension at back and dangly bit at front
Obsolete hairpin (R)/on-average-waist-length robe (mid thigh on left, armpit on right)
Tome:
Ronkan visor with dangly bits/floor length robe (ankles occasionally visible)
Deepshadow hood + optional face cover/shin-length scale-armour robe
Crystarium hat with curtain round the back/floor-length knitted robe
Cryptlurker hood+mandatory helmet/floor-length grubby robe (open at very front from upper thigh)
R:
Edengrace circlet + mandatory feather/ floor-length robe
Edenchoir circlet/ankle-length robe(waist length at front 90 degrees)
Edenmorn top hat + optional spectacles/calf-length robe (waist-length on front half)
Endwalker:
AR:
Panthean hat with curtains round it/floor-length robe (windows for knees down)
Hypostatic mask with curtains/floor-length robe (front knee length)
something vaguely greek sounding probably circlet/yet another long robey thing
Tome:
Moonward ff4 rp hairpin/low cut mid thigh skirt thing with ankle length split cape
Radiant visor/floor-length robe with leg windows
Lunar Envoy's hairpin/shin length robe(no sides on legs though)
Credulous circlet/shin length bathrobe (with cape to ensure everything's obscured)
R:
Asphodelos unibrow circlet/mostly knee-length robe(sides waist length, back heel length)
Abyssos flaming mask with horns/regular jacket length top (with burning shoulders)
Anabasic hat with curtains round it (kind of like the panthean one tbqh)/floor length robe (with floaty sparkly bits)