Mythic Lead Designer Kate Flack has an interesting interview up on Gamasutra about her experiences with developing MUDs and how she's rejecting the industry standard when it comes to crafting Ultima Forever (legal disclaimer: This online multiplayer title is not an MMO, but hey, it's online Ultima so shh.).
Flack says that because most MMOs are based on a DikuMUD standard, they all more or less play the same. She says that there's a freedom to starting from a different standard and developing from there: "It's a way of playing that doesn't necessarily have the same assumptions underlying them. It gives you a breadth of background and heritage that you can pull from. Just because it's always been done that way doesn't mean I have to do it the same way."
Part of this design shift is in asking "sophisticated questions about ethics" to players, which is a vital part of the Ultima franchise. Flack says that Ultima Forever will be more nuanced and involve tough choices that will make a personal impact on gamers: "I want to make you stop, think, and go, 'Huh!' and then learn about yourself, because games can do that."