So i got to thinking, The main problem to Backstabs is the fact that they Instolock/Teleport/Stun you, generally while you are attacking (because when you swing your weapon it forces your back to them)(which on a side note is totally unrealistic.)
Why not just make it so its just (enter # Here)% extra dmg to your Attack if you attack from Behind?
The Main issue in any game thats game breaking is because you generally cant power threw it. In ANY fighting game, or game where 2 players battle it out, if you can't trade blows, or at least clash with something its generally Too strong for its own good (unless balanced for that nature).
Like when you attack someone from behind, or hell the "Aft Side" of the Character you deal 50-60% more dmg, and then some daggers can be made to increase that dmg by another 40%, and then they can change the ring to make it an extra 50%.
So trying to go for the backstabs (they way the HitBoX is set up right now) may get you some nice dmg, but you might also get dealt some serious trading Blows, and possible get staggered which generally leads to death. So now a backstab build would be fun, and skill based because trying to always get it off will most likely get you killed.
[instead of instantly stunning the player for the duration, Players simply do 60% more dmg when attack a player from their Aft Side, these damages can be increased with certain weapons and rings.]
Thoughts? Btw the numbers are just a basic rundown of the idea. if i get this idea concrete enough ill send it over to the Main DarkSouls Forum.