The problem with people expecting every bit of feedback to "matter" is that most of the feedback is actually only being given by a few dozen people at most, out of the million people who bought the game. They will probably pay attention to OVERWHELMING feedback on an issue, but the same 30 people posting over and over about something isn't actually that significant.
There's also the fact that's more or less the only useful feedback you'll ever get.
The overwhelming majority of your future user base is never going to give you explicit and detailed feedback.
Hell, a large part of it will not even be equipped with the knowledge and experience necessary to dissect a game or judge its isolate parts individually.
For a lot of "casual audience" there's just "liking the game" or "not liking the game". They won't be able to tell you what needs to be changed about your UI, controls, mechanics or writing.
For instance KillerRabbit proposes an in-game survey, which is not a bad idea in general. But here's what's going to happen with one:
- let's say 30% of the people playing the alpha will actually stop to compile it (which is a lot, no complains here).
- Of these, let's say one tenth will have specific opinions on specific aspects
- the remaining 90%, the bulk of users, will probably follow a pattern along the line of "voting 10 for everything because they like the game" or "Voting 1 for everything because they are pretty pissed about something".
I know super-dedicated nerds can be extremely vocal (and occasionally extremely obnoxious) about aspects that most people won't even pay attention to, but just because a flaw isn't immediately apparent to the the oblivious majority of your user base it doesn't mean it doesn't affect your game in same way.
