In my experience so far, the 'power' of a witness is not so great unless it is backed up with a great deal of vote power behind it. Previously I have lost a lot of vote power just for dissenting from what the voters think they want, based on what they thought I wanted (which actually was being largely misunderstood). The main power of a witness in terms of changing Steemit is in choosing which hardforks to adopt, but the process of actually creating hardforks to choose from is a long, complicated one which the average witness is not involved much in. I think that making suggestions for changes to Steemit and gaining community support for them is something that everyone can do, so the power balance is still largely with 'the people' on one level.
One of the problems with any kind of banning is that, just like the 'legal' systems of the world - there will always be people who feel they have been poorly treated, especially if they are banned from posting. Users can easily then create a new account anyway, so I don't really see that banning can achieve much.
One of the suggestions I made a while ago was for a new 'page of shame' in the site that allows us to easily review who is being downvoted as a way of exposing abuse of both the payout pool and the downvote system. That could help, but I find that any suggestion of in any way weakening individual vote power or free speech will result in a lot of complaints.
hmm all valid points.Though, I'm honestly not so sure that ruling by committee would be
unpopular. After all it would be a very rare instance but yet a powerful message to anyone moving in and looking to destroy the system. First step could be to have the witnesses vote to even have a vote and then the user base has a vote. Not something done regularly, i would even hope it would never be used, but at some point there should be a system in place to protect the ecosystem. It was supposed to be flagging, but I'm not sure that is working