Over-reliance on lore is not just bad storytelling, it's anti-storytelling. A story is always a process of unfolding, in which events engender qualitatively new possibiilities about what could "be" (i.e. each new event creates verisimilitude for other events, the "world" in which they transpire only one of countless possible embeddings compatible with the series of events.)
When it is only possible to clarify a story through injected "facts" from outside, not only does this have obvious effects on just enjoying the story, it also crowds out the story's ability to indefinitely generate its own novel ysstem of orientation.