What would it or they be? What would you love to find in a MMORPG? Be it a brand new title or a existing one, doesn't matter.
I'd love to see a truly living world. With new, small events added every 1-3 days. With unique rewards (unique abilities, titles, summon-minions, unique weapon/armor model, unique housing decorations etc.) and a kind of newspaper tab in game where you can find breaking news (<Player's name> defeated <Boss name> and earned <Item's name> / <Player's name> opened the golden gates leading to a mysterious location and earned a title of <The Golden>! Hurry up and discover hidden treasures because the gates will remain open for 3 hours only!).
Opening the gates would require finding 4 golden books that could be hidden anywhere in the world. Of course these items wouldn't tell you "collect 3 others and take them to <Location's name>, you would have to discover it on your own.
No wiki & stuff, just every day discovering (would be hard with data mining I guess...). It would be a great opportunity to make people feel unique. But this would also be a great thing to discuss on forums. You could share your discovers with others and think how to make the puzzle work together.
Such system would work in Guild Wars 2 for example (During pre-launch phase, I was thinking that dynamic event would be changed every few months or something...) Single-completion dynamic events chains awarding something unique.
A non-class character creation would be lovely too. Instead, you would choose characterstics of your toon (physical strength, will power, magic aptitude etc.) and their "power" in 1-10 scale and then you would gain starting skills based on them [Everyone would be a half Summoner tho. Because I'd love to see a game where you collect different minion summoning abilities, where you can upgrade your existing minions, give them weapons and armors etc.]. You could also write a short bio of your character that would be auto-upgraded every time you complete / achieve something (with dates, kind of diary in your bio that could be "inspected" by other players). This with addition of one-time events only awarding unique skills (could be a slight particle change, totally different particle or a completely new skill with both unique particles & effect), unique minions, unique skins and so on would result with no two the same characters.
Continuing the theme, I'd like to see a real archeology. You could dig anywhere in the world to find something cool that nobody else has. In-game shop would offer digging-time reductors, detectors that would make a sound whenever you step on an artifact etc.
This would work in GW2 too.
The perfect game, containing all these features would probably be a sub based. It wouldn't be cheap to made.
I know that making such a game would require A LOT OF WORK, money, people, time and that I'll possibly never witness it in my life but dreams are dreams. So, what are yours?
EDIT: I repeat the last part of my comment from the 2nd page to make things clear:
VRMMORPG (Sword Art Online etc.) - well, I don't mean such "feature" in this thread to be discussed. I think we have a thread about it here anyway.
Maybe, if this therad turns out to be popular, I (or someone else, willing to do so, like Fencers? :3) will post a "recap-summary" of the most popular ideas from here. That would give us a brief vision on what the next truly succeful MMORPG would need to look like.