I understand what BRAB is saying. Back in the day Arad was responsible for putting cinematic Marvel on the map and stopped the likes of Roger Corman from butchering more movies like FF. He negotiated a lot of the Marvel movie deals that keep Marvel from going into receivership. Therefore it could be argued Arad was more important than Fiege because he helped keep Marvel as a entity from going out of business, than Fiege who helped set up the MCU (with Arad) because if Marvel had gone out of business there would be no MCU to set up. So like BRAB said, it's debatable who was more important for cinematic Marvel.
That said, Arad has lost his 'mojo.