Just because they're asking for feedback doesn't mean they're doing whatever the playerbase says. They're still developing the game the same way they usually would, except that now they get to see what people like and don't like before the game is released, rather than after. This allows them to make informed decisions about what to work on, what to change, what to leave alone.

Game developers (and developers of all kinds) have been using this process forever. The only difference now is that the people testing the game is all of us, instead of the designers, or a handful of paid game testers over in WotC.

It's doing for RPGs what the web has already done for comics. It's allowing the end user to participate (indirectly) with the creation of the thing they're enjoying.