Goebbels was the mouthpiece behind Hitler, wrote the speeches, the doctrine. Most people think Goring or Himmler, but Hitler I believe was afraid of both and put them at opposite power houses (one had the military and the other the police) so they checkmated each other. I don’t think a ‘more reasonable’ politician would have taken the place. After Hitler killed himself, Goebbels did take the power (for about 1 day before he committed suicide, but still).
Like most socialists, Hitler had already removed anyone capable from power except for a few very hardcore believers near to him which equally would have assassinated him if opportunity presented itself. Just look at the deaths of Lenin and then later the last days of Stalin, loyalist bureaucrats, too afraid that didn’t are lift a finger when Stalin vis-a-vis Khrushchev (initiated the Cuban Missile Crisis) gathered power under their noses.