I've raised this in projects because I don't like the implementations that are on offer for Incremental Reading. It looks like you've got to run Windows for Supermemo, and the fees are pretty high.
What I'd really like to do is have a go at building some kind of scraper / paster where you can get text and build up an incremental reading workflow out of it.
It would also be nice if scheduled spaced repetition decks could show up. This could be from Anki or somewhere else.
I really want this to be bare bones. What we have on the market are tonnes of options that just boggle the mind.
I really like the idea of having a feed of content that helps you schedule readings as described here. Article 
It would be super cool to generalise this to incremental writing too. The idea would be that you have a place where you study your readings, take notes, and practice active recall. If you've read something enough then maybe you have incremental writing littered in there.
At first this would be just topic headings that you'd fill out. You could have prompts or just a quick place to jot down an idea. This idea would be scheduled to come up again and again, but you'd push the priority if it was a "not now" thing.
Zilla Slab all the way. Font
There's a port of Readbility to Go. Github