Hi,
http://www.openfietskaart.nl/?zoom=10&lat=52.15952&lon=6.02828&l...
Good example.
object placement. [...] avoid placing objects on top of each other.
Exactly that can (of course not for all purposes) be an advantage instead of a disadvantage. In mapnik, often information is simply omitted due to overlap avoidance. This is bad if I am interested in a special topic:
If I am interested in parking, I don't want that a parking garage is left out because there's a nail polish shop in the first floor of the same building.
Of course it would be good if the user could sort and stack the layers according to her priorities.
Kay