Couldn't you take this into consideration in the vector renderer? A lot of roads and paths in OSM have width and surface tags, you could render that using some appropriate texture on high zoom levels instead of the usual dotted lines for paths. Forest and grass doesn't have to be solid green fields, and crosswalks and traffic lights could be rendered, contour lines can have user specified intervals, and so on. There's lot's of additional detail you can render parametrically from data.