The point I'm trying to make is that I don't think that MMOs are really in competition with each other, because most gamers don't play only one title. Sure every developer would love to boast 10 million subscribers for their games, but honestly I wouldn't be surprised to see some of the smaller title devs having just as much fun with their games as the folks over at Blizzard have with their title. I wouldn't even be shocked to think that some of the other dev teams actually thank the WoW devs from time to time because there is no better testing platform for a new idea than WoWs huge player base. I think Blizzard hit a needed nail right on the head when they allowed WoW players to customize their interface any way they chose, it was pleasant break from the relatively small view ports in EQ, and the complete and utter lock down on the FFXI interface. A lot of the tools that players have created have been integrated into the actual client once the dev's saw the popularity of the third party applications.
I think that this sort of evolution in the genre is what is needed to take that top spot, to not only trust your players with coming up with great ideas for the game, but to then take those ideas and build them right in. I'm going to be a little self-indulgant and go over some of the things that I have come to love in MMOs over the years, and hopefully some of the developers who read Massively (I know you're out there!) will take my brilliant notions and put them in their games (or hire me to do it, I work cheap).
Customizable Interface - World of Warcraft
As I stated above, I think this was one of the greatest breakthroughs in MMO titles as far as making a more friendly environment for the player base. Being able to make your UI look and feel any way you want goes far beyond just being able to drag and drop chat windows around the screen. Within 10 minutes of first playing WoW, I had already installed CosmosUI (the top dog back in the day) and never looked back, since then I have gone through a number of pre-made UI's and then started to build my own personalized packages, streamlining the UI to a point where I can literally play blindfolded. I don't know if I would have stuck with the game as long as I have without this feature, simply because I can completely personalize the game to fit my needs. I'm a hot-key maniac, and as such I don't need to have my screen cluttered up with lots of bars of buttons, I just set my abilities to hot-keys, hide away the bars and go to town. This gives me more screen real estate for maps, mob info screens, chat windows, damage meters, and threat counters, all while still leaving a relatively huge view port to play in.
Last year I hopped into the beta test for Tabula Rasa, and the first thing I tried to do, before running around shooting bane was to try to change the default UI in it's entirety. When I found out that I pretty much couldn't do anything other than move a few windows around I was disheartened, it actually made the game less enjoyable, to the point that I finally gave it up a few weeks ago. And recently I mentioned going back to FFXI, I was loathing it's lock-down in full screen mode, but was happily surprised to note they have allowed a native windowed mode, without having to risk the GM's wrath using a third party windower. The UI in FFXI was never a horrible thing, because it's very minute and out of the way, so after changing the colours, and a few options with the chat box, I wasn't too fidgety for things like Omen, and Cartographer.
An immersive story - Final Fantasy XI
Something that always kept me going in the dystopian grind-fest that was FFXI, was the story line that you could take part in at every turn. Sure you weren't really in the story when you were spending your fortieth hour in Boyahda Tree grinding spiders, but when you hit certain level caps, you could step away from that and literally be immersed in the ever evolving and expanding story of Vana'diel. There was just something great about the cut scenes built into the game, where your character would walk up to kings and dukes, or where you would encounter the elemental gods. Certainly games like WoW and Lord of the Rings Online have a story line, and boast some of the most in depth lore out there, but rarely as a player do I really feel like I am taking part in it. A friend of mine constantly goes on about how he wishes WoW had cut scenes, not in the traditional cinematic style of console or first person games, but in the way that FFXI did, using nothing more than the in-game models, but taking you into the game for a moment. I will never forget the hours I spent with my static going through the Promathia missions, and relishing the cut scenes involving air ships, gods, demons and my party. I truly felt like I was part of it then, a hero of the ages, and just by /checking me, people could see the deeds I had done with the title system (which, by the way I adored).
Content for the everyman - WoW, PotBS, Tabula Rasa
Something I think WoW did right, that I've seen more and more in recent titles like Pirates of the Burning Sea, and Tabula Rasa, is the idea that not everyone wants or can spend hours on end in game grinding levels and trade skills. Anyone who has ever gone from a crafting system like Final Fantasy's, to the pleasure palace utopia that is the WoW crafting system knows what it's like to really work for their trade skills. And outside of that, a lot of the newer games allow you to go through content on your own or with friends, instead of demanding you find a perfect party set up, thus tying you into at least a few hours time working together, for wont of your reputation on the server. I think the ability to literally get online and play for thirty minutes is great, it allows more people to access the game at their own pace. There are players out there who have been playing for years, who still haven't managed to hit 70 in WoW and are completely content with their progress, because to them, it's an occasional escape from the every day. Whereas I know people who are still playing FFXI, and have only barely managed to get a single job to 75, and they grind day and night to get there. The idea of the hardcore/casual rift in players, is something that is slowly becoming less important. Certainly you have people who will always complain about others getting 'welfare epics' and saying they haven't put in as much time and effort, but I think those voices are growing fewer and farther between as more and more people realize that MMOs don't have to be a second job anymore. You can get just about everywhere in most games these days, with half the effort that used to be required.
I suppose at the end of the day, there will never truly be a perfect MMO, but I think the idea of an evolving genre, where dev teams can build off of each others ideas, will only lead to better and better games. Does that mean WoW may one day be toppled? God I hope so, because that's going to be one hell of a game... but it doesn't mean I'll stop playing WoW when it arrives.