Thanks - yes, there are potentially many other points I didn't touch on.
I'm not sure I agree with your first point since I've been getting decent payouts since I only had a few hundred steem and I didn't buy any of it. The site is intended to reward quality content and for solving problems - I think if users actually do that then they can thrive. It's a good challenge and inspiration to be able to test your ideas against a captive audience of readers and thinkers in this way.
I have seen that some of the whales have been powering down for a while, but I'm not sure that has effected the price of steem to a problematic level or not - I appreciate they could all pull out at any moment, but that would equal a general catastrophic loss of confidence in Steemit for some reason that would probably have a different ultimate cause than just their own personal need for cash.
I agree about Copyright and general legal issues - my exploration of this theme so far has only led me to the answer that 'the founders don't really care about the law'. lol.