I'm not suggesting that people looking for feedback should buy the product first. I'm suggesting that the people giving the feedback should have experience with the product in question. The feedback from someone who hasn't bought the product or operated the product has very little credibility or substance.
I disagree, I think most of us have had enough experience with video games to know how much content is worth the money. $20 is a lot, it can even be the difference between being able to pay your bills on time or being forced to postpone them and hope you can take the hit.
For me, I would rather wait.