You can only be seen on the diagonal with Ghost armor.
I did not know this, and this makes all the difference for me.
From my point of view, it just seemed pseudo-random whether or not I could be seen. I haven't worked out when I can or cannot see cat girls either. I just try different angles until I see them. So with the ghost armour, without being able to predict whether or not I'll be seen, I never felt safe unless I was behind a wall or something. It felt like basically a less effective version of an ordinary melee soldier.
But if I know that the diagonals are how I'm seen, then I can use that to my advantage. I can know when I'll be safe and when I won't. And so I think I'll be able to get a lot more use out of it. Thanks.