I think that by the time Paul was murdered that he and Nino were on the outs because of Paul being dragged into Roy and his crew's stolen car ring case and from what's been written Roy and Paul never liked each other.

as far as Gotti I think people's resentment and hatred towards him during those years is GREATLY exaggerated. it seems like resentment started when he became boss and started forcing the weekly Ravenite meets, flirting with the press and all the nepotism.