If we compare about how many critics out there to how many idea/suggestion out there than we will surprise that the suggestion/idea is not even get to 10%. If the company focus on the critics than the company will get very big headache. Why? Because they have to find the solution themself.
What about idea/suggestion? I think this is the coolest thing of feedback. The suggestion help the company to improve their solution to the problem. And talking about the idea, I can say that it's worth thousand of golds. But as you already know that it's likely very little people out there who can give suggestion/idea. Why? Because it's need deep thinking/analyzation. So why don't you give some rewards to that people. A sincere thanks letter I think it's enough.
Also the company can create contest idea. The coolest idea will be rewarded with present/gift/money/etc. I think if we want to think out of the box than we should accept other people ideas. Don't count on the suggestion/idea from expert out there. Why? They are thinking to much about complexity. We should give the user a chance to submit their ideas because it's from their perspective (from the consumer point of view). We create the product for the user not for the expert right?