I think he has all the right to criticize the new film. However I would disagree. I think many star wars fans enjoyed the retro style. I personally was disappointed with episodes 1-3 (midi-chlorians?). Many people asked for more X-wing and tie-fighter sound.
I think the term is seller's remorse. You give up your baby for adoption, you lose ALL control as a parent. How could he not know that? It appears Disney is doing a fine job creatively and fans will get to experience more of the franchise.