I… don't think we're watching the same show. Either that or you're reading a few too many fanfics. Celestia is wise and kind and all, but no one is aspiring to be her; living up to an imaginary standard is exactly why Lesson Zero happened. We haven't been able to see much of it, but she obviously has a normal personality. She's shown fear, awkwardness, childish joy, mischievousness, and annoyance.

Celestia isn't a divine goddess, nor an embodiment of any concepts. She's a long lived pony who so happens to be the leader. She has flaws, emotions, and weaknesses.