Harpoon has, for all its history taken you to your target. If he’s flying or not, you can deal with the consequences of dropping to the ground, either using Disengage, or your parachute, or anything else which suits you. You can even just hit him in the air while you’re both falling.
Now, just five minutes ago, I harpooned some guy flying and I was sent to the ground right below him at immense speed, instantly killing me from fall damage.
I see a guy attacking people from a roof? I harpoon to him, only to be launched below the building, essentially making harpoon useless in this scenario.
What gigabrain intern at Blizz HQ thought this was a good idea? Despicable