I don't happen to believe in an "inner child" as a straightforward, reified entity. And it also doesn't make sense to take what are forces like id, ego, and superego and try to make them into little people inside us. As some have pointed out the ego is the negotiator between the impulse toward satisfaction of primal desires (id) and internalized societal "nos" (superego). The ego is a reality check and sometimes equated with the self, but obviously in this theory (which not all believe in, even psychoanalysts) there are other parts.

There are more contemporary theories who describe "self states" and especially with traumatic events, a part of the self is left with the trauma at the age of the trauma. These self states can appear when the traumatic material comes up and be "younger" than the current real age. I see it as a flow of different states rather than a little person inside.