for the stack part again its tick damage, mirage got changed into dot suptype of damage where it cant event drop you from ziplines if you get marked and jump on the zipline
the range limit was put for mirage being too annoying and forcing hes engagement range to a shorter and more dagerous space rather than been perfectly safe with no context from a mile away, its a similar reason you cant increase bebop uppercut airborn duration so it wont be annoying making it more fun to fight