I think it is mostly a question of effects. Blink jump acts as a fainted manoeuver dazzling your opponent (on his/her screen). If your coming from the back, there would be no true reason to use blink melee, except for gaining a little range, to your advantage. As for myself, I prefer trying to tick 'em off so they turn around and battle... Although the attack (to prevent frustration) should garanty landing damages as soon as you have targeted and pressed "RB", the hitbox then serves as reference for the level of success of the melee hit. Meaning that if I sent melee to a gardian facing me, I am sure to deal him at least little damage in situations where he runs out of hitbox AND (my favourite) overkill if I calculated correctly space notions... I would expect the player to know what distance is required to perform, in optimal range, the so-called blink. Concerning backstabbing, I would tell you not to forget another human is actually controlling your target. It is totally fair for them to get the chance to avoid the attack, either by running/sprinting or turning around to hit you in a rush. Lets compare to elements: When your enemy has void shield and you strike it with arc element, you don't mind dealing fewer damages. So, because of the angle of the melee attack, the player should consider having failed his pursuit by rushing into backstabbing, without allowing the opponent to engage in an adequate fight. Therefore, blink strike needs some sort of target lock. An interesting alternative could imply an extended hitbox which contains more presice scale of potential damages. Yours truly, I hope my ideas, one day, will come in handy.