I love substack, and have been writing a weekly blog on it for over a year now!
Do you have any plans to give more granular data on traffic/emails? Stuff like being able to see specific posts views over time, etc... What's currently available is ok, but I'd really like to be able to get as much data as possible and then export it into a BI tool.
Also, for a "quick win", have you considered adding the ability for authors to generate unique URLs for sharing posts? Ideally with separated analytics.
A forward/backward button at the bottom of a post that would lead to the next/previous post would also be great