Hmm... there are some unwritten rules about posting to threads that have not been posted to for a while. Perhaps I'm breaking them now, but hopefully my offense is not that serious.
Anyway.
I like the idea of briar showing in minimap. And actually wrote a java program that extracts minimaps from hold using the same palette that is used in the game except that it shows the briars also.
But I think we need to remember that rooms have been designed when briar does not show on minimap, and sometimes briar might have been chosen because it is invisible on the minimap.
I don't know how much other people look how the map when designin levels, but for me it is important. So adding huge blobs of strong color like purple to my maps would make me sad
So, as a compromise, I propose a light gray color such as the one used with bombs. Perhaps a bit darker and slightly green.
Something like #AABBAA. This color is clearly visible at least on my monitor, and at the same time neutral color that does not change the minimap too much. An also this color should be different enough from other colors used in the map.
