I very rarely get a back stab kill but even then it is still on a WAY slower recharge rate than shoulder charge. On top of that hunters have less speed then a titan. You will never see a blade dancer rush through the middle of the map and melee charge you. At least I have yet to see that lol. That is the difference. Shoulder charge is offensive. Blink strike can be offensive but it is not going to be used in a rush. It will be used in a 1v1 or a melee or shotgun battle.