I think I get your requested point... but: Let's forget about size/opacity for a minute... help me understand why only arrows "always visible" (instead of on mouse hover) is different than any other hover object?
For example, in the below there's a down arrow hover image (for going back downstairs), a left door hover image, a girl chat hover image, and a right door hover image. If one wanted the "arrow" images visible all the time, why not just make all the hovered images visible all the time (the other images have a white outline when hovered to note they are selectable)? The arrow images are no more important than a door image in these cases.
View attachment 3137108
I'm not implying your request has no basis, I'm just trying to understand what makes the arrows any more important in a free roam than any other selectable image on the Player's screen as they navigate.