I feel that there is more than simply impact on the readability but also on the semantics. When I feel clueless about a topic I look to comments with up votes

I feel that there is more than simply impact on the readability but also on the semantics. When I feel clueless about a topic I look to comments with up votes to get a general feel for the direction of the discussion and hints how to educate myself on the topic. On your first suggestion: Maybe it is hard to work with absolute thresholds as the amount of votes is probably proportional to how long something stays on the front page. Maybe there is some measure to determine when a thread has begun to "settle" down and that would be the time to make votes visible.