>by removing the border, maybe even flatten the texture. it's just a suggestion though, might work out with simpler icons alone as well.

i think with "Icon" you mean the one that is displayed on the brass plate. of course you can set any icon you want.

>"ourselves" as in "we who provide the original content". Obivously we can't force our design decisions onto the community developers who add their own custom markers.

i think you misunderstood how the markers work. the icon (in the picture: the chest, lorry, dynamit or clonk) can be set via script. thus, everyone can make their own markers.

>Looking at the dark, blocky images of lorry and chest, I really couldn't distinguish them right away. We'd definitely want some simple, remarkable shapes with good contrast against the background.

as said, the icon can be manually set by everyone via script. so you can make a good distinguishable icon you want for every event you want to cover.