multiple of these.

personality:
- factotum

- some characters seem to use animations that make them look shy or timid like Hildegard from the Dark Brotherhood.
that'd be cool as a personality

- a personality that lets my character use a cane/staff whilst walking, without changing their posture.
Just like when you stand with a Restoration Staff.

- treasure hunter, but with a differently coloured flame on their torch like the npcs in Apocrypha that have green flames.




hair:
- azure ombre version of the Adorable Assassin and White River Braids hairstyles.
- or just a way to dye hair and use that specific colour for any hairstyles.



mounts:
- a cherry blossom indrik
- an autumnal indrik for the autumnal indrik pet
- more multi rider mount types? a bear would be awesome.
the mount customisation you mention in your poll would be cool too.



eyes and head adornments:
- separate categories for eyecolours and eye makeup please please pretty please zos.
i really want to have my characters use eyeshadow, eye colour, dainty antlers, scars, and facial tattoos all at once.
- if not possible then more Facial Hair like Winter Princess Glamour would be awesome as it has both eyeshadow and lipstick.


races:
- maormer for new playable race please.
it could be added with any island zones,
some islands connected to hammerfell like the Chain or Cespar.
or the islands south of Valenwood.
or Pyandonea itself.

- reachfolk
they could look like Bretons or some mix of that with Nords/Imperials and only have different passive skills.
and of course some extra dialogue in the Markarth DLC.

- Lilmothiit
- Kothringi
if they aren't truly extinct either one could be added in a future Black Marsh chapter.

other humanoid khajiit furstocks
- ohmes, looks like bosmer so should be very doable to add.
- ohmes-raht, have tails so only slightly different.
- dagi-raht, about a head shorter than minimum height bosmer.
- pahmar, about a head taller than maximum height altmer i think.

other types of argonians
- naga, which we've seen in Murkmire and Blackwood as part of the Dead-Water and Sul Xan tribes.
- haven't seen them in lore, but maybe there's more that also only have a different head that i can't remember.



for Skill Styles:
- i hope for more Warden bear colours.
- green clannfear for the Clannfear familiar.
- if possible a way to make the Scamp familiar wear a pack like the Undaunted Porter pet, it'd be so cute.


outfit styles/costumes:
- First the option to hide tassets and the option to hide loincloths.

- ithelia's outfit would be pretty cool.
- a skirt style without leg warmers please.
- small ankle boots
- a non class restricted Soulcleaver Mask.
- Sanguine's Rose
- what the Voidmothers wear.

- more Aedric Knightly Order styles like Knight of the Circle which is for Arkay!
maybe first for Julianos, Dibella, and Zenithar as those got Arms Packs recently.

regular clothes!
- a leg and chest style combo for a dress?
- all the clothes we can steal that npcs wear all throughout the game.
- heeled boots.
i think the Off-The-Shoulder Evening Dress costume has heeled shoes, but the dress almost always covers them.
- short pants!


- the option to remove effects from Arms Pack weapons and the new class styles.
i especially want to remove the purple flash from Prior Thierric weapons, it hurts but i love the design of the weapons.

would be funny
- mask styles for daedric princes we fought like Molag Bal, Mehrunes Dagon, and Vaermina.

costumes:
a version of the Off-The-Shoulder Evening Dress without the side things and with a smaller skirt so the shoes are visible.

Maormer. Maormer. Maormer. I'd make so many Maormer.

Also, more hairstyles, particularly more styles of ponytails and buns.

Character wise I don't need anything as imagination can cover anything I'd need, but there's definitely stuff that can make the game more rpg-like.

Actual choices in quest chains.

At the very least main quest should offer alternate routes, different outcomes be it minor things or the very end of plot. It's a painful experience getting back to ESO after literally any game with quests. Last time it was Necrom after Elden Ring. Yeah, that was a pain no boss can inflict on you.

Better writing.

It's a subjective one for sure, but the decline in quality was noticed in community at large for years and main line plus first dlc considered as best ones to this day without any competition. When game generates so much money I don't see a reason why writing is on a level of tumblr fanfic. Especially when we're told that they're changing writing and being hit with the same stuff all over again like it was a blatant lie.
Hire an established writer, please.

That would be next level in ESO indeed.

For better immersion mount customization would be nice, especially if it were possible to leave all the gear off when placed in a house. I'd like to have them roam free when at home.

Also, it would be nice if the companions could keep the costumes you dressed them in on when you place them in your home so they can fit in better with the theme you chose? That would probably be a lot of work for the devs though.

Dialogue options that allow for some degree of self-expression. Maybe something like "Personalities", but affecting the text that we see our characters speak.