Well, you are suggesting something that might very well not be possible for this forum. Your pop up, or form already in the reply section, stuff like that I don't believe can be done, at least, not with what we currently have. We'd need a new plugin, possibly a plug in that doesn't even exist yet.
I agree more productive comments need to be made, but what you are suggestion most likely won't help much, if at all. Most people woudl rather just write what they want than to fill out a form, no matter how small. The people that would spend the time to fill out the form are people who already offer good or at least decent comments, and wouldn't increase their worth much. And for people who don't give very good comments, it woudl discourage them from posting at all, which would be somewhat of a good thing. And the people who don't post comments for cards at all, will want to post comments on cards even less, or just continue not caring.
Spam posts are already frowned upon, and many are dealt with if they pose a problem. Most people just ignore those that post worthless comments worry about the actually good comments. But i would rather "it's op" or "it's up" than nothing at all. It might not be much feedback at all, but it's still better than nothing.