I disagree, man. Lennon the person had a direct impact on Lennon the artist. If i can be so bold, John Lennon was the most self-absorbed song-writer of all time. He nearly always wrote about himself and his issues. Help, Walrus, Norwegian wood, Wheels, etc.. Look at Plastic Ono Band - one of the most brutally honest albums of all time. Lennon once said he wanted to make music to strip away any illusion, any metaphors, to make it as raw as possible. And while it may seem like a trip with the shrink, it is chilling in its initimacy.
Lennon had many faults as a human but lucky for us - it made for a great artist. Like Picasso and Pollack, Lennon was a self-absborbed swine who made excellent music. As Miles Davis said about Charlie Parker, he was an evil, selfish greedy pig...but aren't most artists?
I wouldn't want John Lennon as a father (neither supportive nor lloving ask Julian) - Didn't Lennon spend like five years not seeing or talking to his own son...(too busy chasing Harry Nilsson around) and i sure as hell wouldn't want him as a friend (jealous, insecure, vindicative (ask G HArrison) delusional) but i damn sure would want his music by my CD player.