Thanks for your feedback !
I worry about duplicate content hurting the SEO
We are still thinking about how to alleviate this issue. Delayed posts, cannonical urls, backlinks, we'll see but I'm confident that it will be sorted out.
I am concerned about all the plagiarism bots.
Like a lot of people here apparently ! I think it's not an issue, all of these people have whitelists and if you start using steempress and notify them, I'm fairly sure you won't get flagged, I mean they act for the good of steem to avoid spam. They wouldn't go against actual original creators coming to steem.
Finally, I have multiple niches.
Yeah it's an issue that's been here for a long time on steemit. In the future we'll implement some filter functions on SteemPress so you can choose one category and post only articles from this one. But yeah unless we setup a system where you could post each category in one different steem blog, it'll be hard to fix it on our side.
I definitely think some delayed posting options would be good. And cannonicals and/or backlinks would help.