You're right on the money. The earlier WB Cartoons are certainly funnier than Disney's, but they were still trying to emulate the Disney style, and hadn't found their distinctive voice. Avery began the change, and his influence, along with the development of Porky Pig began the entree to what eventually would have been WB's 'golden age'. From the mid-'30s on the cartoons just keep getting better and better. More creative and audacious, and any vestige of "cutsey" was gone by the end of the decade.