We've been getting pretty cosy with Final Fantasy XI recently, and while porting various existing massively multiplayer games to the 360 is very much sought-after, we're hoping that developers will really take the 360 into account for some upcoming titles. Here's a wishlist of features we'd like to see in 360 MMOs:
Full Xbox Live integration
Rather than have separate friends lists for the game and for Xbox Live, link the two together so you can see what your Live friends are doing. Similarly, have the MMO provide a series of achievements to boost your gamerscore--anything from hitting the maximum level to logging a certain number of hours or defeating a particular boss.
One problem with existing MMO models as ported to the 360 is monthly charging--as Xbox Live already charges, scrap the game's monthly fee altogether. Instead, use an optional micropayment model based on Microsoft Points to unlock content or, if the economy is designed well, convert points into in-game cash.
Provide multiple multi-person private voice channels, allowing quest parties, guilds and friends to converse together, and allow them to be created automatically--for example, when a party is formed. Provide good-quality voice transforms to allow players to gender-bend their voice as well as their avatar.
With a clear interface that's easy to read on a normal television, and an input system designed with the Xbox 360 controller in mind, an MMO on the 360 must remember what platform it's on. No scrolling lines of indecipherable text--no hard-drive install--take a leaf out of console RPGs' design and keep it simple.
Take advantage of the immediacy of the console to make fighting more interactive, requiring input from the user such as pressing the right trigger to slash a sword. Auto-attack should still be an option, however. Clever use of shoulder buttons, ABXY and the D-pad should mean a large set of abilities can be invoked during combat. PvP should be fast-moving, skill-based and integrated into every level of the game.
Let 360 players game with their PC buddies, let international players group together, and address problems of platform equality (for example, it's easier to hack game files on a PC client) from the very start.
It's a tough list to satisfy, but we're hoping.