In terms of the reason I am no longer in the top 20, at the time of the Steem/Hive split - I would not vote in favor of freezing the Steemit, Inc. tokens. I have always maintained the position that witnesses should not be getting in the business of freezing user tokens, unless it was specifically to address an issue of chain security. I knew at the time it would cost me my witness spot, but I was OK "dying" on that hill. My post on the topic is here.
I also created my own version of the fork code that would still allow them access to their tokens, but would prevent them from using them to vote on witnesses. I posted about it here. It was not enough for the stakeholders who wanted to completely "eliminate" the Steemit, Inc. mined stake though, so I've been outside the top 20 since then.
RE: What are your expectations of Hive witnesses?