I think the film does show a bright perspective of life. In the scene we see Ziegfeld's wealth when he gives the doorman a 5 pound tip for information and with the bouquet of "all the orchids in the world" for Ms. Held, but this film is about Ziegfeld's life, a time prior to the Depression. However, the film was made and viewed during the Depression. Also, watching how people had the time and resources to enjoy the frivolities of life would have possibly provided hope that America would survive the Depression. At the time of screening, Americans would not have known how much longer the Depression would last. This film would have been great escapism for the time.
I think some of the themes that will continue to be seen are ones about women choosing between men and between work and man, that a man can make a woman a star, talent isn't always necessary for success, and it'll all be better tomorrow.
If this movie had been made pre-code Ms. Held's costume would have been a fraction of what it was. She certainly wouldn't have been covered from head to toe. No big bonnet hat or parasol. We would have seen skin and probably sequins and/or spangles. While it's easy for us to understand the double entendre in the song, the words would have been naughtier pre-code. As it is, she repeats the same phrase many times.