I agree with your final notes.
I don't think the site is anywhere near perfect as far as curation though. That is contributing to the frustration of many users.
The promoted tab needs to be improved. A number of users have made suggestions as to make it more beneficial to promote a post, such as incorporating promoted posts into the trending tab, and having promoted posts listed in the sidebar, as well as various means to ensure the promoted tab posts are shuffled a bit. Fixing promoted posts will go a long way in reducing the problems of vote buying.
You can also pretty much just set a bot to automatically upvote posts by users that are statistically more likely to have a high reward, and sit back and collect the curation rewards. This causes a lot of posts by well known bloggers to be artificially inflated. You can see this on any of their posts by the number of votes they get literally seconds after posting a blog post that is over a page long. Unless these voters have a neural interface, they're botting it. In my opinion, there need to be lower curation rewards for users that are more successful, which will mitigate this, and cause people to look a bit harder for quality posts by unknown authors.
Communities will likely help to find quality content, but I don't think they solve the issues.
The problems with bots have occurred because of seemingly small issues with the platform. The only way to get rid of them is to work together to figure out ways to mitigate them.