Feedback from other humans(players or developers or otherwise) is limited by what they see in front of them...it will tend to express everything as a surface issue of either polishing, expanding, or cutting parts of the game. That can be very helpful when you are trying to get a sense of how "much" you need to execute on a concept before people understand it. Things like finding out where people are getting stuck or confused, adjusting difficulty and balance are solved through this process.
For working on the basic concept of the game and figuring out major features and scope, you can get better feedback by developing your own rubric like the writing rubrics used in grading school papers, and "grading" the current game against the rubric to see where it succeeds and fails at the vision you have - abstract things like "what is the game about, what should the player do and feel," and so on. When the game is failing something in the rubric, that means you have to iterate, but that doesn't mean it takes a big change! It just means that you have to make a big shift in your perspective that wasn't obvious and might feel uncomfortable or contrary to what you wanted at first.
That's where feedback from people tends to fail, because most people will come from the same perspective and can only suggest changes in small increments. When it comes to conceptual issues it's very hard to get the information you need just by discussing it at a low level. A conceptual failure that isn't polished tends to result in comments about what could be polished("I don't like the keyboard controls, could you add mouse controls") and then once you finish off every polish feature requested, you get silence.
With multiplayer games and virtual worlds there is a tendency for the community to take "ownership" of the game once it crosses a certain level of success, becoming resistant to any change. Then you will have to learn to be a politician. But that means having enough players to be successful first which is not guaranteed - it's far more likely that you get an empty server.