What gamers want

I'm currently playing Star Wars: The Old Republic pretty avidly.  That and an occasion dabble of League of Legends.  It's funny how different they are.  Star Wars is an MMORPG rich with history, scenery, immersive stories.  League of Legends is basically a simple tower defense game with a stable of characters you can play with.
SWTOR is very possibly the most expensive game ever produced, but has been plagued with a loss of subscribers, some pretty negative feedback (though it was initially reviewed well), and seemingly a loss of support from EA, its publisher.  League of Legends, on the other hand, is a free to play game that is becoming an unstoppable force, easily eclipsing Call of Duty 4: MW as the most popular PC game, maybe even of all time.  LoL has an estimated 15 million active players, surpassing even WoW's vaunted 12 million mark.
The odd thing here is if you look at the feature roll-out with Star Wars, it was prioritized pretty close to what the community was demanding.  And that's after the game received a lot of positive initial reviews.  So what happened?
I think game developers need to be very careful when it comes to gathering feedback from the community.  I think there is a very simple but powerful phenomenon here - and that is gamers don't always know what they want.
Let preface that by saying gamers DO know what they want at a very simple and abstract level.  It's different from gamer to gamer, but whether its the raucous laughter at a hilarious piece of dialogue or the sweet satisfaction of that last kill after months of frustration, what gamers really want is to have a good time: or fun.  But how do gamers have fun?
Let's go over 3 of the elements in MMOs that are commonly thought of as wanted or unwanted:

A) Grinding sucks
Many common MMO elements are somewhat repetitive nature: aka the grind.  This is now universally denounced.  But there are 2 very important reasons why they exist.  A) They keep players occupied and slows progression (necessary to develop a time commitment that makes leaving a game harder), and B) To increase the satisfaction of the end result of the grind.
What I believe players don't realize is that removing the grind doesn't make them happier, it only makes the reward worth less.  It also removes something to do, which then in turn can results in the player getting bored. Developers need to strike a good balance here because too much grind is boring inherently.  I think ideally you want very little grind at the very beginning so you don't lose people immediately.  Through the early mid game, you want a fair bit of grinding to make rewards worthwhile, and then taper the grind off as people are more and more time committed to the game.  Still, don't remove it entirely, as you do need to give people something to do and work towards.Bored players unsubscribe or quit more than frustrated players. They also complain about lack of content.

B) MOAR CONTENT NAO!
Speaking of content, let's talk about that for a second.  Content, by itself, can't drive a game.  I don't believe its physically possible to develop content at a rate that most players can easily outpace.  It's also not necessary to make a great game.  League of Legends has basically no content, and can be incredibly addicting and fun.  SWTOR has tons of content and is not meeting expectations.  Content isn't always a bad thing - just look at Skyrim or Fallout 3, but it certainly isn't the solution for a game that is boring players by not having enough other compelling elements.

C) Exclusive limited items are awesome!
This is a specific subset of limited items - because I think everyone who plays like limited items to a certain degree.  Without them, the game risks of becoming bland. However, if the item is too exclusive and meant to serve as a badge, this concept backfires. I've heard a fair amount of 'hardcore' gamers say that the game needs this.  I disagree.  While a small number of players will have their e-peen stroked by their badge of elite gamer awesomeness, the rest of the community is left out.  So while the initial reaction is exciting, I believe long term this is an overall negative experience.  It also likely won't satisfy the truly hardcore gamer (that is actually able to earn this item) long term.

There is an initial reaction when looking at these elements in an MMO setting, but perhaps it isn't as clear as you think.  Sometimes, when things don't feel fun to you, it makes something else more fun. Or maybe it just sucked to begin with - who knows?