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.