So it can be safe to say everyone has thier own idea of what would help to make thier onw perfect MMO, well here is a few things I would consider paramount.

1.  Solo of Team Play possible from level 1 to Max, a game should not exclude one group or the other, not should it force people to team if they do not wish to, or make thier advancement hit brick walls unless they do.

2.  Excellant Crafting Sytem, for me I enjoy crafting, I do.. others like to beat each other over the head with big sticks, me I like to make stuff.. it should be expansive but not overly complicated.  For the record I think Lord of the Rings online has a very good crafting system, the crafted items being better for the most part than the majority of what you can find or earn in quests, especially if you get a critical success with the crafting attempt.

3.  PVP and PVE,  some people seem to think a game can only be one or the other.. I disagree, I t can include both aspects perfectly well, however it should not FORCE one style of play or the other one people..it should be a choice, as such I am very much in favour of games where PVP is done by flagging, everyone can go and do everything same as the next person, but for those into pvp they can flag themselves as such and they and like minded people can beat the snot out of each other to thier hearts content without interfering with the PVE crowd.  Some games like EVE in my mind get it drastically wrong by designating this area is PVE and this area is PVP.. but then design a game where you can experience the most interesting aspects of it solely in PVE lands.. forcing you to go into pvp territory and get preyed on by frustrated hormonal 10 year olds with the literary capacity of a stoned gerbil... bad game design.

4. Mounts from level 1,  lets be fair apart from trying to prevent people from sending money to their alts or buying in game cash online there is no real reason why people shouldnt be allowed to buy and ride mounts from level 1, yet every game feels the need to make it a high level benefit.. I dont really see the need, the cost limits availability and if someone does send cash from thier main to an alt to buy a mount then what difference does it make, who does it hurt? how does it hurt the game? simply put it doesnt.. so why limit thier use and availability.  Better to save unusual or rare mounts for things that have a level limit on them, and allow horse or whatever the standard mount is in a particular MMO to be obtained by anyone.

5.  In Game Housing,  Im a big fan of in game housing, somewhere to dump my junk, or decorate with my hard earned wall mounted balrogs nostril..  Some arent fans of housing I am, instanced hosuing works really well without cluttering the in game maps.  One little oversight most mmo's have however is in make the instanced housing communities more interesting places to be than just to store stuff.  The ability to include crafting stations in houses like SWG would benefit some other mmos.  Also the ability to start a shopfront or player stocked vendor etc.. these would give far more reason to vist and check out these places... some games like LOTRO could benefit from learning this.

6. Transactions over  Upkeep,  I hate upkeep mechanics.. pay X each week/mponth in game to keep a house active or a vendor operating, I hate it.. mostly because of my gaming schedule being so unpredictable, miss a week or a month of being able to get online and your screwed, your stuff is dumped into escrow or as with some games just pure vanishes and your right back to square 1 and costs a fortune.  Some games try to make this easier by allowing you to pay in advance by a period of time a month with some, as long as you can afford ina dvance with others... however the main gripe I have with this is it makes a game less fun, less time for questing etc.. as your forced to grind income in order to pay in game bills... DEAR god if that isnt too much like real life tedium I dont know what is.  As such I'd prefer a game where I can say I want a house... pay XXX amount of in game currency to buy the deed and then pay a single one off in game real £££ transaction fee to activate it, at which point I never have to pay anything ever again, Ive bought my right to a house, or ship or whatever and I dont have the tedium of in game upkeeps to worry about. 

7.  In Game GM's  this used to be a given back in the day there would be GMs on call each day ready to give help, answer quests or resolve issues then and there... no hours/days/weeks of waiting while a ticket for support is answered and some copy and paste response is recieved, by which time whatever the problem was is long since gone or forgotten.  Not to mention it would encourage better behaviour.. how many inappropriate Global channel conversations do you think there would be, gold seller adverts, or abusive/innapprpriate or racist arguments on game channels do we think thier would be if thier was someone of authority online and in game right then and there in order to ban or speak to those involved at the time.  Heck this wouldnt even have to be a paid job im sure with most games there are a good many experienced, mature and repsonsible players who would gladly volunteer to fill such roles in order to keep thier servers much more pleasant environments for people to play.

8.  MAssive Choice in Character Customisation, I have to say my eyes were opened wide for the first time when I first played City of Heroes and was cofnronted by just how much choice in appearance they provide you for your character and even after years I rarely see two characters look the same very often.  Many mmo's should learn form this... obviously content should take precedence, but it is also important to remember these characters are our online avatars our in game presences they are who we play and whome we are associated with online so the more option to make them visually individual and unique right form the get-go the better in my opinion.

9. Guild with a Point,  Okay maybe its just me but most guilds on any mmo tend to be playgrounds for a group of high levels to do thier own things, while everyone else although talked too and occasionally helped is largely ignored until they too are high enough level to participate in the high end stuff... wow is a nightmare for this kind of exclusion but many other game ssuffer the same problem too.  As such guilds needs more point than just to be emmembers of, they need to be able to contribute other things to its members beyond simple aesthetics like the guild name under your own, or tabards, custom rank etc..  Guild Halls./Keeps that are upgradeable, Guild Vendors stocked by player made or found items.., Guild Quest givers for all levels etc..  they need more thought and attention given to them.

10.  RAce to have a point as well as Class/Profession,  one of the things that annoys me greatly with many mmos is howa race has no bearing on the class/profession you choose develops only on which you can choose..  Obviously it require more work on the developers part but seriously how does it not make sense ot devs that (using WOW as an example) a Blood Elf Hunter should be totally different to a Midnight Elf Hunter..  dev response well it is different, they may pick different talents... my response yes but from the same pool of talents so the potential for sameness is still there.  Instead there should be generic talents/powers/abilities that are in common to all hunters, but thier should also be racially specific talents/powers/abilities that are available to members of that race only when choosing that class.  In this way the race you choose would have far more bearing and relevance in what you play.