Kane

I thought the scene where Kane is releasing his anger out on the room and its furniture was a good example of the dualistic nature of being both powerful and powerless. He looks like King Kong. He is portrayed by the camera as a giant but looks weak and old in the way he walks. He looks like a dumb, drunk giant about to collapse at any moment. He is breaking everything because he just lost his wife, Singer. I think Singer resembles Kane's mother here in her departure from Kane. Kane loses love. He realizes the meaning, or lack there, of the material world and sees that he cannot buy his love just like he cannot buy his mother back or Rosebud.
Now that we know that Rosebud is the sled. I recall the scene where Mr. Bernstein is speaking about Kane's past and says, "A man remembers a lot of things you wouldn't think he'd remember." He then talks about how he remembers some random girl he saw once. This is a clear indication to how little Rosebud means to everyone besides Kane. I see what Mr. Bennett means by watching the film multiple times. There's definitely more connections you can make by rewatching it.