I think of the Star Trek series in terms of siblings in a family.
TOS is the first born, eldest child that gets everything and can do no wrong. TNG is the second born who tries to live up to the elder sibling by exceeding in school and other activities. DS9 is the badboy who constantly gets in trouble. Voyager is the quiet child who reads in the corner and everyone ignores. Enterprise is the child who is overwhelmed and cannot walk out of the shadow of the accomplishments of its other siblings.
Thoughts?