It would be cool if the stealth hero had some sort of time delay weapon. That way you could plant a bomb on an unsuspecting enemy and have it go off once you had cleared the area
reaper already has teleports and the problem with the shaded areas is that you will just learn to check them all the time
the problem with those other options is that all of them let the enemy know that you would be around and would make them try to hunt you down even more
Abilities don't necessarily always have to be something you want to always press to make something happen - counterplay is important, and understanding how people might react within the context of counterplay is equally important. Simply having opponents be aware of and afraid of something can be used to your advantage, as can baiting enemies to come hunt you down away from the objective. Just ask any Widowmaker, Genji or Tracer.