Honestly, I don't think having curators to write also reports to justify their votes is a good idea. Most of people here on steemit have a work and their schedule, curators primary task should be to read posts and suggest a vote. If I remember correctly, to get voted posts need the approvation by 2 curators: this is the transparency control. The best would be to have at least 2 curators per language (or even 3!), to speed up the evaluation process and avoid post getting translate to english, with more work for english curators. Having more curators not only will make evaluating process more transparent and fair, but will also speed up things up.

As for number of posts: there is really little we can do about it. Steem is way down in value and top authors prefer to not invest so much time in writing good and deep content if they are getting a really little reward in STU. This is why all authors posting right now, for me, should have a "bonus" and getting higher votes when they hit a certain quality level (for example all 65 posts getting a 100 vote, if VP is ok).

Also, as you already suggested, It would be nice to have more comment engaging. This could be done also by voting comments with the steemstem account, maybe with a 20% power, in order to get a nice reward. But this require a lot of effort, more than the honor members, by the authors themselves. In fact, it would be really hard for a guy to track all comments on STEM posts (I think people will just read posts they are interested in) while it's way more easy (and fair) let the authors report (maybe in a specified channel) the posts where valuable comments are written.

Last but not least: I think It would be really useful to have something like a technical comment under low rewarded posts. Some people just think that re-writing things found on wikipedia or other common sources is doing "STEM posts" and this generate lot of misunderstandings and complains. What if on posts voted for less than 65% , steemstem bot use a different post comment, sayng "your reward was low, if you want to know how to improve contact us on the discord"? This way we can make the "question and complain" channel more a "question" one and less "complain/beg" channel.

Anyway, thanks for the hard work on this project, I really admire all of you guys! Let's hope the market will get up soon!