Shout out to anyone that remembers the Mushy Pea juggling shop in Manchester many years ago, where I learned all sorts of circus skills.
Unless you start throwing feathers or balloons, the latter requires you throw higher. That requires you to either spend more time launching them up (bad for the ‘decrease time between catching and throwing’) or use more force (bad for throwing accuracy.
Also, even assuming you juggle 4 balls keeping “time in hand” equal, you have to throw it higher by a factor of (4/3)². That’s almost 2.
And even if you manage to make those throws with the same accuracy in angles, the errors in location by the time you catch the balls scale by the same factor.