Let me just start by saying that I'm a player who has gotten to CP720, has 6 fully leveled character, but I have not completed all vanilla content on any one character. I have done most dungeons, vanilla trials/MOL, and most DLC areas, and I've completed vMA a few times on one character. I say this because I want to make sure that it's known that I've experienced most of the content in various degrees and a lack of content isn't a part of the arguments I'm presenting/asking to talk about. This discussion is about giving more options to access veteran content throughout the game.
So when it comes to ESO, I'm completely dedicated to it and I love its gameplay for various reasons. I like that you can effective builds can come in many shapes and I love that my classes aren't defined by the MMO trio outside of VERY hardcore content. That being said, my favorite part of the game is metagaming. I love making more niche builds, like my nightblade tank/healer or a 2h DPS, mostly because I'm not trying to use those characters in particular in trials (or can swap out the build when necessary). That being said, I played this game because I love Elder Scrolls in general. The lore and story telling in ESO in particular is good, outside the stagnant animations and tedious directions quest npcs give. My favorite part about the quests is discovering new and interesting things about the world and exploring it with my boyfriend, which I use to bounce ideas and theories off of. But that's where the problems start to begin for me.
When it comes to any roleplaying game, there is an aspect of challenge. You can raise the difficulty on Skyrim, for instance, and die plenty of times if you don't understand your build. You definitely can make the game easier for yourself, but for the most part I was still presented with a chance to die fairly. Dragonbreath one hits you unless you build resistances, bandit chiefs randomly execute animation you if you're not careful, mages tend to do 5x the damage your spells do, etc. Even after min maxing, I think most people agree that at least the game keeps your interest because it's more dynamic. Now, ESO is more stiff in the overworld and that's fine, because the game can challenge you with various combat mechanics to spice up the combat, and you especially see that in dungeons but, if you stop long enough to see it, there's also instances of this in many of the zone bosses. I personally loved Barbos in Morrowind even if he was a complete push over for a max level character.
This is where I'm left longing with ESO. When One Tamriel first came out, the one thing that inspired my boyfriend into playing the game again was that all content was available and the areas scaled with you. It made exploring a lot more fun at first, but then after a while you realize you'll never be met with a challenge. We finally went to Craglorn, tried some of the public bosses, and that's where we were finally having fun with the mechanics and finally being challenged. It was a blast until we ran out of stuff to do and realized that all the rewards and sets, outside some motifs, weren't worth repeating it over and over again.
A lot of MMO fans went to ESO and expected an MMO, which they got. They got a game more dynamic then a lot of them but they still got their 4 man dungeons and their group trials, eventually their battlegrounds and dueling. Outside of various balance concerns and a demand for more group content, their needs have been met. So what about TES/RPG fans?
I came into the game expecting to want to duo with someone throughout the world. I loved duoing in various diablo clones/neverwinter/etc. I longed for a co-op TES experience more so than with traditional mmo groups of people. That sort of gameplay doesn't really represent the dynamic of a TES game, but at times the overworld can. It just lacks literally... any challenge. At all. It's been proven that it can be solo'd by people with no CP 10x over, and not only does it not present any challenge, it also teaches nothing about the game's group content or PVP. So what is it really there for outside of being a barrier for ESO's more entertaining gameplay? Decent storytelling but otherwise, few rewards and fewer challenges.
With the new Chapter looming over us and Morrowind acknowledging only some of these issues (World bosses had double the hp of vanilla, had more mechanics, public dungeons provided more challenge and unique rewards, overworld enemies were a bit stronger and had more interesting attacks and interactions), I think it still has a long way to go. While I believe new exploration and solo content is good, I think there should be a push to make more interesting, eventful, and rewarding solo content that, at the very least, might push a player to ask for a duo or player assistance and might push for more of a communal interaction with the zone. Doing world bosses is fine, but what about vet delves or public dungeons? What about repeating quests with stronger enemies and bosses(I really like the looks of some zone main quests, but I have no desire to go through it because the gameplay feels like a choir)? What about DLC zones specifically being centered around working together with others or otherwise being more challenging, like Craglorn (Murkmire anyone???)? What about content specifically made to challenge, like maelstrom arena? Cyrodiil fort sieges, but PvE horde modes? I could come up with stuff all day.
I think the game comes out with plenty of solo content but fails to see that it's all streamlined and even casual players have no reason to come back if everything feels repetitive and unnecessary.
TL;DR: If ZOS intends to focus on making massive explorable every half year that isn't challenging, but release group content that could be either challenging or casual, why can't you do the same to an extent with the solo content? Focus more on player duos and rewarding group exploration. Make growth in ESO more dynamic and don't always have it focus on group content as the only intention to reach end game.