I think Lucas definitely had this in mind with regard to bringing balance to the Force. The Sith aren't the "yang" to the Jedi's "yin." Rather the Jedi have lost their balance by trying to trap "the living force" by way of rigid dogma. Anakin fell because his love for Padme was possessive and thus easily exploited; Luke succeeds because his love for his friends and his father is self-sacrificing. But no strict dogma can tell you when exactly one thing becomes the other; Luke is on the precipice in the Throne Room scene and he has to work it out for himself.