Its a dead stat that only increase walk speed, strafe speed, and increases the distance traveled[be it X or Y axis] of the first jump only[does not effect second or 3rd jump]. & decreases movement speed the higher your mobility for titans & warlocks. Making it increase it sprint speed would be the best option as this would benefit all 3 classes. Lets be honest its weird 2 of the classes gain movement bonuses for suppressing the stat, while the 3rd class only gains a class ability CD reduction for investing into the stat but no movement bonus. [i]Edit: For the 1millionth time, mobility currently does not increase your sprint speed.[/i]