I agree with you entirely that fear needn't be the only teacher that leads to growth.
Maybe a more appropriate word for that growth-inducing state is being "uncomfortable". I think uncomfortable is more manageable, and a little easier to retreat from when you need a moment to breathe. Fear sounds more severe and primal in a way.
Also, I think we have quiet epiphanies about reality that aren't scary at all. For instance, a stranger and I got into a conversation at a coffee shop the other day and the topic of "being certain" came up. She expressed wanting to have guarantees in her future. I pointed out that while we want certainty, if we knew everything that would happen, life wouldn't be very fun. Simply being told this made her more comfortable with ambiguity and uncertainty. No fear required!
I think it's wise of you to point out that over-emphasizing fear might not be wise in terms of self-development.
Great post :)