You are talking about binary compatibility and immutable dependencies. That's nice, but it's a different topic to the conversation that jerf and I are having about the semantics of shared code. I'm sure maven is good at what it does, but it's not completely relevant.
Fine, then let me put it this way: your initial claim in no way matches my experience. "Beware the Share" is bad advice; that wiki page is simply wrong. Factoring out common code is a good thing and will not bite you.
It's a wiki page, but it's also a book [1]. I have an actual paper copy, and I would highly recommend it. I've seen several of the authors give talks, most were good. Kevlin Henney (the Editor) was particularly so.
However I shall also treat the data from your deep experience with all due reverence.