Those seem totally valid and well thought out reasons. I have to admit I have been on here actively for 2 months now, and have never flagged anything. I just havent really seen any of those things you mentioned. I tend to find folks I like and really read most of what they write, so I dont get around as much lol. Also I try to avoid drama like the plaque as I think it robs the joy out of the experience on this or any site.
If it were up to me, I would like to see the rewards distributed slightly differently. I would like to see more folks get a bit more at the expense of the few getting slightly less. If it were up to me I would probably have a earning cap on each post. Flagging doesn't seem to be the appropriate method to achieve this I suppose.