It's the trees, you see. Well, it's the trees and the rope darts. In previous games your assassin - Ezio or Altair or Desmond or whoever - was certainly capable of dealing death from all manner of directions. He could stalk his prey like a lioness on the serengeti, moving through throngs of people like they were blades of grass. He could definitely swoop down on his target from on high with ease if he chose, and if he ran fast enough he'd get away before anyone could do anything.