On my servers I usually use a chunk generator (Chunky) to pre-generate a giant area around spawn, so there are no performance issues while people are playing. This however makes exploring the map boring, because Dynmap already spoils everything. So my request would be to add a setting where the map is fully rendered by Dynmap but an area is hidden on the web interface, until a player walks through that area (with configurable radius).

Edit your configuration.txt, and look for the section related to Triggers for automatic updates, then just comment out the - chunkgenerate line with # at the front, and restart. You can generate without it loading on dynmap then.