Here’s and example of a map that tanked. It’s a horrid example of both too much and too little, of oodles of detail but lack of vision and design.
In the adventure, the heroes chase an armada of cannibalistic pygmy outrigger canoes through the night to front of the Accursed Isle. The pygmies bind the heroes’ companions, and any heroes they’ve captured, to the tops of cyclopean pillars just barely jutting above the water. These sacrifices are supposed to weaken the gods’ spells imprisoning the Great Old One in the island’s foundations. When the heroes arrive, nasty mythos monstrosities are crawling up out of the sea to feed on the prisoners, and a battle ensues.
The map is dizzying. The grid is too faint to make calculating distances easy and too prominent to make the water look compelling. I ran out of time to render any real texture on the cliff front, so it looks like plastic, and it presents no feeling of loft or scale. I would have loved more time to try to work out these problems, but this may just have been a bad idea from the start.
Sometimes less is more.