I'll start by saying that I'll be using comparisons to Wow, a very successful MMO. Not as to what should exist or how systems should be, but rather how to keep the player engaged. My main focus will be on PvE aspect. There are very good threads that already talk about the pros and cons of the PvP scene. My only input will be is that they do a great job at letting the player engage how they want Right Now. With talks of trying to disperse the big groups, I have my doubts PvP will still be as engaging as it is.
The MMO genre has been around for sometime. There has been a lot of growth as to how to keep players engaged and to keep them feeling excited about logging on. It starts with a rich background of content and, in my opinion, no franchise has more of that than Elder Scrolls. If you need any proof as to how popular it is, Skyrim is ranked within the 20 most successful games in history. But there is also design, which again, Elder Scrolls does so well. Big open spaces full of life, full of activities. But you need to disguise those activities as something that's new, something that makes you forget that every game has the same initial inputs and outputs. That's where ESO needs to add to and where Wow does so well.
My first run through, I was thoroughly engaged. The quests were soo good at masking what the underlining goal was: Pick up object A, Kill object B, Find and turn in Object C. They were funny, they were smart, they grew through the zone as any good quest design should. But then it stopped. It stopped because of Cadwell's Silver and Gold. It now became a chore, a chore to reach end-game. I was pulled from the concept of supporting my faction to be placed in another faction as.... Undercover? Spying? Living the life through someone else's eyes? Nope, simply to continue the monotonous grind to level cap. Wow has done this well. You get to chose from several zones where you want to go. Leveling a new toon can feel different depending on which zone you chose whereas leveling a new toon in ESO, you have the same zone next in line. Whether you make a new toon in EP, AD, or DC its the same zone that you're forced into, removing player choice. So you'll get the same quests, usually, in line. You'll get the same armor and weapon rewards.
The next problem is once you complete Cadwell's goose chase, you're off to Craglorn. Craglorn itself is a nice change of pace. It's a bit tougher as now you'll need to begin group quests. This has good and bad tendencies. It helps prepare you for organized trials and veteran dungeons, but now go several months to current time, its a pretty desolate area. You'll see a few level capped players soloing mob packs in the veteran 11 portions, but no longer are chunks of the community advocating group quests, if many were. Most chat pugs would be advertising farm groups as it was far faster to grind specific key areas to maximize time to exp gain.
Lastly are trials and Vet dugeons. The game is a year old. Let's be honest, a revamped new release is not going to make it feel new and refresh. Only new content does that. Content in the forms of new quest zones, new hubs, new dungeons and trials. Adding two new pieces to old content is not justification as new content. For players that have been here for even 5 months and have a level capped toon, that becomes stale fast. Champion Points...... CP...... On the top looks fresh and interesting. Underneath it all, it's more grind than the payoff. 3600 points is unfathomable in a players mind at the gain of one a day. You just told players you have a 10 year plan in character growth. Do you have a 10 year plan for content, in terms as discussed earlier? Do you have a 10 year plan for expansions? The consumer doesn't want to hear they have to play every day to stay current. What happens when there are years dfference in player power. A 7 year player versus a 2 year player. That's massive.
These are my concerns of longevity and player interest. These are shared amongst the community.