Personalized news - This is something I've been missing in many newsletters I get in my mail. It would be nice if you send news, article, etc. based on the nodes one follow.
Update: I saw that the content of the newsletter should be already personalized, but it doesn't feel so. At least not in the last 2 newsletters I checked. I will see the other ones and update further if necessary.
Rearrange the newsletter - What I look for in a newsletter is a valuable information. The sooner I find it, the better the chance to stay and read the whole newsletter. Sharing a quote is a great idea, but you should think of a better place for it.
Less clutter, more value - This is related to the point above. There is just too much text and the links get lost.
Picked Answers - Something I was really keen on was the Picked Answers section in the old newsletters. It showed one of the strongest parts of Hashnode - the community. It's also so satisfying to see your image out there. :)