In terms of the problems caused by the "shard" model, however, this is only the tip of the iceberg. Shards were an effective solution to a technological problem in an era when MMOs were a niche, minority interest. Back then, the chances were that you only knew a handful of people who played MMOs, and arranging to play on the same server as them would be fairly straightforward.
Today, however, MMOs are an important and growing part of the mainstream gaming market, which has itself become a vastly more pervasive and widely adopted hobby. Many people starting out in an MMO will have several groups of friends who are playing, or thinking of playing, and the chances are that they'll later meet other people who play the game. Arranging to play on the same server as all your friends is next to impossible - and discovering that you are already on the same server as a new player you meet offline is extremely unlikely.
Needless to say, this puts a dampener on the idea of playing an MMO as a social game. Bizarrely, it makes more straightforward multiplayer games such as Halo or Call of Duty into more fundamentally social experiences. Certainly, you can only play Halo with a few dozen players at a time, but crucially, you can play against any selection of players from around the world. Any friend who owns the game can hop online and play with you - while with World of Warcraft or Aion, the chances are that if you discover that your friend is playing, you won't be able to play together anyway, since he'll be on another server. End of conversation. You both play a multiplayer game, but there's simply no direct mechanism to allow you to play it together - which flies right in the face of the whole concept of online gaming.
These issues, from Aion's queues to the frustration of being unable to play with friends in WOW, are made all the more annoying because they no longer have a technological justification. Today, it's eminently possible for a game to be created in which a character can easily hop from server to server, playing with whichever group of friends he or she sees fit. It's not hard to envisage a system whereby you log into your character first, and then select a server based on the people you want to play with at that particular moment - instead of logging into the server and picking your character, who is tightly locked to that server, as occurs in games today.
It's been a long time since I could lay claim to the job title "programmer", of course, and there are indisputably both technical and design issues which such a system would create. However, it's increasingly apparent that sticking with the old way of doing things is not a realistic option.
How much further could World of Warcraft grow, if people could simply play with their friends whenever they wanted? How badly damaged will Aion be by the negative perception created by its overcrowding problems? This isn't simply a question of players being a bit annoyed - it's a question of MMO operators leaving vast amounts of subscription revenue on the table, simply because they're wedded to a convention that's over a decade old and no longer justified on any technological grounds. Any developer working on a new MMO who's still stuck in the rut of forcing players to pick servers and stick with them needs to seriously reconsider - it may be "how we've always done things", but this is one tradition that demands to be put to rest.
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