I agree that Davis made him the scapegoat for New Orleans, and his northern heritage seemed to be a liability. However, shelving experienced men like him and D.H. Hill would seem to be a luxury that the South could ill afford, notwithstanding the personal feelings of Davis.
I would be interested in other opinions of Lovell's military qualifications. Seems he could have been put to some kind of use, perhaps even in the Trans Mississippi graveyard.