Strict moderation can still be effective once obscurity is lost. /r/SpaceX is an example of an excellent subreddit that has survived an explosion in popularity.
> So your post sounds a bit to me like "Twitter is great if you know the hashtags to follow" and it's probably true but at this point is it really representative of the website? If you need to filter 99% of the content to make it usable, maybe there's a bit of a problem still?
You're just making the observation that the majority of internet users aren't sophisticated intellectuals. Demanding that the website you visit are sophisticated everywhere is just a demand that they are hidden or ignored by most people. I don't see how this is different than having hidden/ignored hashtags, subreddits, or filters.
Normally when people find a forum that interests them (like, say, HN) they need to bother creating an account, often validating an email etc... It only takes two minutes but that's enough friction to weed out the vast majority of the people who just stumble randomly on one of your posts. On Reddit once you have an account you just have to click a button to subscribe to any community you like. It's "eternal september" on steroids. 4chan had "lurk more", Reddit is "repost more".
So your post sounds a bit to me like "Twitter is great if you know the hashtags to follow" and it's probably true but at this point is it really representative of the website? If you need to filter 99% of the content to make it usable, maybe there's a bit of a problem still? I just went to /r/all and had a look at the subreddits available there, I find 16 million accounts subscribed /r/gifs, 3 millions to /r/politics, 17 millions to /r/gaming, 18 millions to /r/pics etc...
So yeah, I'd believe you if you told me that /r/common_lisp, /r/mongolia/ and /r/treepics/ are amazing communities but I don't think it's enough to redeem Reddit as a whole.