As one of the less technical users on SN, I vote for 4. Downvoting could allow for more refined feedback on content so users can fine tune what resonates and what falls flat with the community. If downvoting were somehow gamified with sats, it also adds a novel use case to the format here. Image and videos would be a plus, and paywalled content on a message board seems like another novel use case that could develop in interesting ways.