I think downvotes on proposals (and maybe even witnesses) should be an option eventually.

This should have been implemented at the beginning. Not voting does not imply consent and the ability to disagree with and even absolutely object to a proposal or witness, ought to be a given, there is no mechanism in place for me to say No, I don't want the DAO paying for unrelated law suite....

Great post, lots to think about
Best wishes to you :-)