The thing about Webflow’s CMS is that it offers a visual front-end for building databases. It might not be the most efficient thing out there, but it’s very easy to use. I don’t know for sure if Publii can match Webflow’s functionality, I only mentioned it because their developer documentation made theme development look so incredibly simple (for myself, at least - a non-developer who only knows enough CSS/HTML to get by).
Really, what I’d like to see (and what I was initially hoping to see from Pinegrow) is an SSG/offline CMS with a visual front-end: a visual site builder where I can build my pages like any old HTML, mark-up my pages with {{data}} hooks to pull from an offline database, and export an entire static site out of it — all without ever having to worry about command line tools or learning a programming language.
As far as I can tell, there’s nothing out there that fits this bill.