I understand that your are currently working on the maps section and geographical attribution of caches in general. Maybe it is not too late to consider the following:
Currently cache locations (and consequently filter possibilities in statistics, map compare etc.) are based on three administrative levels: "country" (as defined by geocaching.com), "region" and "state".
For smaller countries this works fine as "states" are sufficiently small to contain a limited number of geocaches, which can all be shown in lists / maps etc. However, for bigger countries with a high density of geocaches even the lowest, "state" level often contains too many caches to be shown on a map. This holds true e.g. for Germany (where the Kreise are used as "states") or France (départments).
If possible, it would be great to add a fourth layer of administrative divisions, which should always be the municipality. In very small countries where it does not make sense to have four layers one or too of these could be skipped as is already done now for some countries, where e.g. no "region" level is defined but only a "state" level.