Hard to discern impassable areas

From any level of top-down zoom, I have trouble telling which land elements can or cannot be traversed.  I'd expect this to be clear from the topographical level view, but it isn't to me.

I know that I can tilt the map to examine a specific area, but that's time-consuming.

So - can we get clearer go/no-go demarcations on the topo map?  Just thicker lines for the impassable points would be a BIG help.

Thanks.