I'm a veteran player of both the Elder Scrolls series, and ESO itself (as well as MMO's in general for going on two decades). Been in this particular game off and on since beta. I'm an avid quest runner and collector of fancy costumes and pets. I'm a part time roleplayer and full-time PvPer (not so much in MMO's), and can even muscle up to complete end-game content when the mood strikes, but find it repetitive. I'll grind for two months for a piece of furniture or cloak, but only two minutes for a piece of gear that is only 2% better than what I have on. I care more about how my characters' looks, than whether he's in the top 10% of stats.
Here is my rather short list of little and moderatly larger changes I'd like to see to make my time in ESO more enjoyable, and give me more reason to play the game:
Interactable chairs, tables, torches, fixtures, and various other devices throughout the world. These are little scripts and animations that can really liven up an otherwise pretty backdrop, and ESO has plenty of pretty backdrops.
More character model options, including thinner and heavier bodies, wider and narrower shoulders, waists, and hips, and thicker and thinner necks, arms, legs and even heads. The lack of variety in shape and size in character models has been my biggest annoyance with every 'modern' Elder Scrolls game to date.
More character options in tattoos, hairstyles, makup options, and 'body modifications' (piercings, rings, spikes, etc).
Barber shops and 'magic mirrors', for making basic and advanced modifications to your characters body shape, hair cut, etc. Makeup and haircuts should be cheap and easily accessible; body modifications and facial resculpturing should be expensive and limited; race and name changes should be cost-prohibitively expensive (as in, crowns) and one-time affairs.
ALL armor is remodeled to look as if it has actual weight and thickness, not painted on. I know they are doing this with new gear, but the old styles could really use a revisit. Is this overall improvement really so costly in time?
Roaming NPC's and mobs, that can interact with one another. I realize the spawn anchor mechanic is a common flair for MMO's, but I believe that phasing mobs to you and your group, until you interact with them (at which point, that mob becomes visible to any passerby who wants to join in and help), should allow the world to be populated with fewer mobs, and make the mobs appear more lifelike.
Stopping mobs and bosses from respawning in public and private dungeons by phasing them to each player or group of players, until they are interacted with, or you/your group moves out of eyesight of the spawn. Nothing kills the mood of a delve more than having a mob respawn on top of you. This would include the boss, preventing any player from 'camping' a mob without first leaving that immediate area.
Every zone leveled to you similar to Orsinium. That area was amazingly free-form and felt more like previous Elder Scrolls games. There will always be a difference in character capabilities due to skill points. And you have to complete one stage of a quest to get the next. So since level 1 players won't be killing Molag Bal anytime soon, why not give the game more freedom for exploration and adventure?
Stop making players choose an alliance, and just choose where they live, when they start. Then let them travel between regions as much as they want. When its time to go to Cyrodiil, THEN make them choose a side as a temporary 'mercenary', free from those loyalties when they aren't there. Let all players adventure together and interact in the entire realm of Tamriel and Oblivion. Makes more sense than what we currently have.
Player housing. I'd prefer GTA's or EQ2's instanced 'one door, infinite apartments' housing to DAoC's, LotRO or EQ's 'housing neighborhoods'. I'd prefer EQ2's customization options, allowing many trophies, wall mounts, or even changing the wall textures/colors, to Skyrim's 'Hearthfire' room-is-laid-out-for-you approach. I'd love to see every option, from little one-room apartments to massive walled citidels, from own-it-yourself to 'you and your guild' affairs similar to what they have in STO.
Guild housing and keep building, similar to STO or WoW. Bought and maintained by active guilds, and give players a lot of the amenities of home. Can also be micro-zones and have many small 'houses' in the surrounding countryside.
Edit: Jan 5th, 2016
Arena fights between two, three or four-man teams, up to three teams total. Capable of spectating, betting, and localized to various arena's in each alliance territory. Matches restricted to three or four minutes, restricting and penalizing quitting and promoting pre-built teams, with the arena's intentionally kept small and simple, only deathmatch style. Separate pre-built teams versus pick-up singles. Something like this may already be in the works.
Small skirmish instances between 10-man teams that involve capturing remote castles or chokepoints outside of Cyrodiil. Drop-in, drop-out functionality and longer matches around twelve minutes in length. Deathmatch, capture the flag and zone control styles. Something like this may already be in the works.
Island homesteads allowing planting, harvesting, mining, fishing, and homebuilding, very similar but more 'in character' than what Wildstar produced. Require massive collection capabilities before certain features unlocked (must harvest so many of a resource before resource opens on your property, to prevent it from being too easy to abuse, etc), and other features would be available only through in-game achievement (imperial throne room if you are a former Emperor, etc).
Emotes capable of being used in chairs, on horseback, while sitting, and the ability to quick-bind different emotes to different states.
Ability and animation for swimming horses/mounts.
The ability to convert disguises into costumes, which would in-turn make it so that the disguise could no longer be used for confusing NPC's, but also wouldn't take up inventory space.
Edit: April 8th, 2016
Ability to control combat pets separate from casting capability, taking summoning/pet mastering off of the limited toolbar.
New combat pets added, including wolves, cats, bears, hawks, etc.
New combat companions, similar to assistants, but only combat capable. Earned through storyline quests for each guild, a few crown store. Disabled in Cyrodiil or other pvp arenas'.
As you can see, many of these are currently 'in the works', so mostly it's just an exercise in patience at this point.
Wishes Granted!
Converting trophies into collectibles, and allowing all trophies to be used in emote quick slots (there are still several exceptions).
Ruze Aulus. Mayor of Dhalmora. Archer, hunter, assassin. Nightblade.
Gral. Mountain Terror. Barbarian, marauder, murderer. Nightblade.
Na'Djin. Knight-Blade. Knight, vanguard, defender. Nightblade.
XBOX NA
Ruze is a veteran of the PC Beta, lived through the year one drought, survived the buy-to-play conversion, and has stepped foot in the hells known as Craglorn. He mained a nightlbade when nightblades weren't good, and has never worn a robe. He converted from PC during the console betas, and hasn't regretted it a moment since.
He'd rank ESO:TU (in it's current state) a 4.8 out of 5, loving the game almost entirely.
This is an multiplayer game. I should be able to log in, join a dungeon, join a battleground, queue for a dolmen or world boss or delve, teleport in, play for 20 minutes, and not worry about getting kicked, failing to join, having perfect voice coms, or being unable to complete content because someone's lagging behind. Group Finder and matchmaking is broken. Take a note from Destiny and build a system that allows from drop-in/drop-out functionality and quick play.