Are all books comparable linearly like this though? I could see separate stack ranks for different genres (practical books, sci-fi, relationships, whatever), attributes (readability, teachability if applicable, subject matter interest), or more.

I also can't help but think in graphs, so I could also see horizontal-ish linkages between the stacks as well. Each book, then, could have a number of attributes that get an independent stack ranking for each one, leaving you with a constellation score as well as a focused look at what the book is good at or focused on. I could see it getting unwieldy though.

Thinking through this, maybe genre stacks based on some collapse of attribute ranking scores.

I think this could work, although perhaps in combination, not replacement, with the traditional ranking system. The book on the bottom of somebody’s list isn’t necessarily a bad one.