I can recall conversations from the past decade when my fantasy-reading friends would hear a certain speculative novel was bland, and they'd immediately ask: "Did it have a map?" A derisive snort followed. Of course, in the decade preceding that, I would buy only books that had maps between their end papers and opening chapters. No map, no deal. How quickly our tastes change.
More than anything, the search for a map was a search for comfort. A means of spotting familiar territory on packed bookshelves. The map was a promise of what sort of story was within: swords, quests, most likely magic. It was the marker for a place I called home. Where my reading-self kicked off her boots and put up her feet.
I've since come to a place where I see no such absolutes, no need for either map inclusion or exclusion. I've lately started to feel that among new novels, the urban fantasies have more maps than the second world fantasies.
But the existence of the map -- so long as it's accurate to the novel's description -- remains, in many but not all cases, a marker of thorough world building. How are we to believe you've done your homework for a realistic set of trials, or a logic-based magic system we can buy into, or indeed, for what "the orcs' loincloths are made out of," if you haven't first planned out the lay of the physical land to house the assorted narrative tchotchkes?