How important are these factors to creating a walkable place?
My intuition tells me that, by far, the biggest reason tighter networks are more appealing to pedestrians is the fact that the crosswalks are shorter and that, if crossing these streets was simply made more comfortable through means that do not necessarily include road diets and new mid-block streets, any pattern would be walkable enough to work.
Minimizing walking distances and providing a variety of routes are, ultimately, not nearly as significant as simply removing the awkward feeling pedestrians have at most crossing places.
I suppose I should distinguish intersection density from crosswalk density and/or the presence of woonerfs, which I believe are both important. Chamfered corners also probably help relieve the relentlessness of a pattern with large blocks.