> One the more thought required to give feedback the less likely users give feedback.
That is great! This means the people giving feedback would tend to be power users that are able to giver higher quality feedback.
> As a side effect short content is very nice as finish/playtime become strong signals that require a user to do almost nothing.
Perfect! It is clear by now that users vastly prefer short content that gets to the point quickly.
So basically 5 stars ranking would vastly increase the quality of the content but that is bad, how?
The only issue I see is (political) vote brigading. Maybe set additional hurdles like minimum account age and the like for voting. Strong content moderation could help. I guess there is no silver bullet for that issue.