Welcome to steemit. :c)
To your points:
In many ways steemit does promote positive enforcement - but it is not always so. It can be difficult to be noticed - regardless of the quality of one's content.
The community is quite supportive overall and helpful too. There are exceptions of course and bullying can and does happen upon all levels (typically at the hands of "high reputation" users because of how reputation works).
As such I wouldn't call this platform troll, negative post or sybil proof.
On the other hand I would downplay the presence of any hate communities. Frankly such posts are few and far between. Of course the boundaries of what one considers "hate speech" and "freedom of expression" can work to shift the posts. Can it be a problem? Yes. Is it a problem? Not-so-much. Plus it could be argued that it is far preferable for such sentiments to exist at the surface where they can be addressed than to be allowed to fester out of sight.
Quantity over Quality 'is' Steemit. There exists little motivation to deliver more than a couple of paragraphs of "content" and a second-hand image per post. They may get less upvotes per post - but the effort-to-payout ratio is King here...
Yes people can copy-paste content here - but they would be caught out thanks to plagiarism-detecting bots. That being said - its far from a complete solution - and some definitely do plagiarize anyway.
Steemit needs a rethink. Its a functioning model - but then again so was the Ford Model-T. ^_~ There is always room for improvement and the dev pool and executive core need to keep their eyes open.