Actually, my idea was to have some kind of chevron in the circle under the enemy, indicating which direction enemies were facing. The only problem with a backstab tooltip is that you need to be in backstab position to see it, and if you aren't, you need to spend another AP to move into the right position.
I've not looked into the underlying mechanics of "flat-footed", "flanked" and so forth. I suggest that without being in stealth, you shouldn't be able to backstab an opponent unless they've another toe-to-toe opponent (aka, why Dark Souls backstab is so broken).
Without knowing the exact bonuses the close combat effects give, it's hard to see if the mechanics are working correctly (i.e. perks are there to prevent being flanked etc).
