I think the other bosses of remaining families in New York thought he was good boss. He had a lot of scrutiny placed on him as soon as Gambino died, yet he had a good run till commision case. Killing DeMeo seems to have been neccesary, and he had it done. If he had taken care of Gotti too, a transiition after him being convicted would have gone smoothly I would think.
The other bosses made money with him, but it doesn't mean they thought he was a good boss. What matters most is what your family thinks of you. Apparently, enough people didn't think he was a good boss that they killed him and nobody in the family did anything about it. Imagine if some renegade capos in the Genovese family whacked Gigante. All the conspirators would be dead.
