There are a few issues at play here and I think each warrants a different solution to some extent.
A high volume discussion doesn't earn a place on the home page if it's controversial
I think the right way to address this is actually to just factor more than just upvotes, downvotes and time into how we sort things. We want the default homepage view to be a list of relevant and interesting topics to whoever is viewing the page, (which could mean that the home page is different to some extent for every person. We definitely want to build a more sophisticated sorting model that could help with this.
If I don't post circlejerky nonsense then nobody will see my post
I think that right now this isn't a problem because there isn't a enough content for some to be "never seen". in the future I think the way this gets solved is varying contexts where in the right context any content can be relevant and highly viewed. If you use reddit as a comparison which a lot of people seem to be doing - you can't just look at /r/leagueoflegends but instead at reddit in its entirety. The #1 post on the LoL subreddit is about streamers crushing low elo players. In the context of LoL it's the most important topic, but on all of Reddit it doesn't break the top 200. I think our plan for this community platform is that there are eventually tons and tons of different communities each with their own cultures, rules, and moderation styles. If your content is not relevant one place, maybe it will be somewhere else.
Thoughts?