Surely, you don't take Berkeley seriously, do you? If the universe is an illusion, the Berkeley's very thoughts are illusions as well and should be ignored. Taking it one step further, I would wager that Berkeley looked both ways before he crossed the street, lest he be creamed by that illusory Mack truck.
You have not answered the question put to you. How is "somebody imagined everything up" different from "God imagined everything up"?