Not if it's so rapid you don't have time to properly enjoy it, or put another way if it's so rapid it clips the top of your progress-detector and all progress above that is simply wasted in terms of your hedonic enjoyment.
I am skeptical of the idea that the smallest of children have the conceptual sophistication to notice and enjoy their growth and improvement. Older children may, but then - adults can improve and grow too, while being competent and productive (and, at least potentially, self-conscious of the growth) all the while. However, my individual perspective is probably uncommon here: I didn't like anything about being a child that has turned out to be unique to childhood.
The fiction piece in this week's New Yorker deals with some of the same themes as Eliezer's "Three Worlds Collide"; viz., the clash of value systems (and the difficulty of seeing those with a different value system as rational), and the idea of humanity developing in ways that seem bizarre/grotesque/evil to us.