Not that hard to program probably, but could make game to easy (or confusing).
Well, the clockworks in my head tells me that it wouldnt really make the game easier, but adds more of speedy reflex reaction from the player. I thought the catching the egg part was already too easy, particularly since (for the levels that i played) that for each egg, it's timed so that you have just barely enough time to actually catch it - if you move fast enough.
But throw in the element of that even if you do move as fast as you can theres still a chance that you'll miss (essentially, the eggs will fall at irregular intervals) that you'll HAVE to (try) catch it in the air....thus adding some chaos to the game...would really make it interesting.
Just a thought!