Hello, so I always have this exact same problems with map overlays playing almost any ARPG, and LE is no exception. So here are my suggestions to slight changes to map overlays so has better clarity.
Objective : show clarity between walkable areas, hopefully more visible in bright/dark maps alike.
Example Map overlay suggestions
Excuse the amazing photoshop skills, but here’s some simple adjustments to help with map overlay visibility.
The first picture is the original, it shall act as the constant.
2nd Image is suggestion to blur the INSIDES of the map slightly so u can tell which is the inner part of the map, and which is outside the map.
3rd Image is another option to brighten (or darken if it’s a bright map, perhaps just a adjustment layering overlay with some histogram levels adjustment would do) the insides to give the same impression as above.
4th is to make the overlay slightly 3D, with some opacity adjustments or darker colours, so it can be seen in any light/dark environment.