I would say that is mostly true. Those he couldn't wrangle (like Marv Wolfman, Len Wein, Gerry Conway) jumped to DC and John Byrne hated him so much that he went to reboot Superman and only returned to Marvel after Shooter was fired. That said. Shooter was a titan and someone made the industry stronger. He was also not afraid to be the boss when he needed to be and was able to make the hard decisions. The Dark Phoenix Saga wouldn't have had nearly as much impact if he mandated that Jean Grey die for annihilating that planet.
I was fortunate enough to meet him one year at the Calgary Expo where I told him that Karate Kid was my favorite Legionnaire. He told me that he created the character because he wanted a more physical character as most of the Legionnaires abilities only required them to point at an opponent from afar. Throughout our conversation he came across as a friendly and genuine person who loved the medium.
Oh, and my mom has a copy of his first published comic (Adventure Comics #346) and it's in pretty good condition despite my constant reading of it as a kid.