(Edit: I don't feel that ESO has been as hardcore as I prefer as I state below. I am giving a review on both my feelings about ESO and what type of game I would ultimate like, personally to be more clear)
Just want to say first, that I love the artwork, and some of the inventive quests in ESO. Not here to bash it, but to share my opinion.
Long story short first: 1. I would love a game that encourages friendship and group dynamics (classes) by making grouping a necessity from the very lower levels on up. 2. Make gameplay and goals more difficult so that players HAD to work together, and depend on ALL classes. 3. Have one guild, not many.
Ok, breaking down some finer points:
Basically, I would love an "old school" type of MMO. By this, I mean one where you relied very much on group interaction. Have 4 main classes that were are very clearly defined. I think this fosters strong guilds and friendships in the game, and the feeling that your class is vital to achieving your personal and their guilds goals.
Next, would love goals (like obtaining a mount or armor) to be harder to achieve, and the penalties for dying tougher. Then it is very gratifying when the guild or group finally accomplishes their goals. For example, in a past game it took our guild 6 months to achieve a flying dragon mount, and it was a blast. It was a very long quest line, very hard to do, but you felt proud of it in the end and I made some great friendships. And it gave players a reason to log on each night.
Making dying harder. In an older mmo; If you died in a dungeon you would have to wait 3 days to retrieve your armor (on your body!) unless your guild/group got your tombstone. Sounds really bad, but it made the game challenging and forced you to work together. Dying almost felt like a real death, haha. Another game took away substantial XP for dying, which seems awful, but you were on your toes and worked hard at your class.
I know many people disagree with this type of MMO, or think that it is too hard or there is too much grouping now. But, I'm going to step out and disagree with this. I think there less communication/friendships between players and within guilds because MMO's have become much easier, and do not stress groups as much as they used to. Friendships and communication was there because it had to be there to succeed.
The need for grouping should be in the first 50 levels, so that players need to join with others right away, not later. This would benefit ESO as well, because this makes players loyal to each other, and the game.
I'm not suggesting everyone agree with me. This is only my opinion. I am just hoping for another "old school" type of MMO to come out again some day. I'm thinking it is not likely. But, I'm pretty sure there are many more of you out there that feel the same way.