The RC system still needs a little bit of work. Post and comments need to be separated out, and separate from each other. they are two different aspects of steemit. Once the separation is complete then constraints need to be put in place. The vast majority of spam comes in the form of comments. As I suggested in a comment to @paulag there needs to be a timer put on them:
Example second post in less than 2 hours cost twice as much RC to post, third one in less than two hours after the second one then four times the cost of the second.
That would take care of some of the rapid fire posting. Two hour time frame is a reasonable time frame, this will I understand hurt things like the pull into steem apps stream2steem or whatever they are called. So not rapid fire twitter recast or steepshot recast or things of that nature. The app designers will just have to look at the time frames.
To really do away with the comment spam, second comment in less than 3 sec's ten times the cost, 3 in less than 6 sec's from the first 100 times the cost. end of bot spam. This would of course seriously curtail the ability of any vote bots to have their advertisement show on the post that paid for their use but, such is life, the bot's would still be able to vote, and that is one thing that should not have a time limit because of curation trails and bot votes.
This will no likely cause a lot more kick back than the posting issues, but the vote bots can adjust their commands to comment only once every 2 or three minutes.
Just a couple of thoughts.
RE: HF20 Update: Operations Stable