As someone rewatching it now, I'm surprised by how few pure filler episodes there are. At minimum, every episode at least advances a core character. And usuall

As someone rewatching it now, I'm surprised by how few pure filler episodes there are. At minimum, every episode at least advances a core character. And usually has one Easter egg related to the overall plot. As you said, compared to TNG, early DS9, or X-Files, this was groundbreaking stuff on broadcast TV.