No discussion of UO ever happens without people arguing about PvP, but that's not what this post is about or what one should take from UO when comparing it to WoW and other contemporary games.

The thing that made UO way ahead of its time was personalization. You could wear whatever you wanted, color it however you wanted, and surround yourself with personalized items. People made gold from selling their creations. There's a lot of talk about casuals and how you can't have a UO-like game succeed because casual players won't like it. That's absurd. You don't think all those gamer girls (and most gamers in general) want to dress up their internet dolls? WoW is a very fun game but it's depressing how it not only does not support personalization, it seems to actively resist it. Everyone looks the same in WoW - and maybe that's largely due to technology limitations, but it's still something that they should attempt to address.

Second Life is an awful cesspool of porn and spam, but the only activity that is creative, flourishing, and profitable is the selling of player-designed clothes and other customization for avatars. Personalization is something people want in MMOs, and UO had a ton of it 15 years ago. Not that Blizzard really needs any help digger deeper into the player's psyche, but if they wanted to hook even more casuals, that could certainly learn from UO.