Shirley Temple was capable of turning in better performances than "Baltimore" as she transitioned to adulthood, but the script (a flashback to 1905?) and the other actors were not people she could play off well.
Just two years earlier, Temple had a major hit with Myrna Loy and Cary Grant in "The Bachelor and the Bobby-Soxer". In this, the script was sharper and funnier. It was in the present day, focusing on Shirley's growth, and she had the dependable Myrna Loy to work off. Loy, while projecting a solid and comedic presence herself, always went out of her way to make sure the other actors were comfortable with her and with their role. In this case, when an agitated Temple kept showing up for work due to marriage difficulties, Loy sent her a beautiful bouquet of flowers and a heartfelt note, bonding the two actors for the rest of their lives.
Loy was the rock in every comedic group of actors she worked with. She went out of her way to allow the other actors to feel comfortable and do their best work, a proactive behavior she had learned when working with Clark Gable, Melvyn Douglas, Spencer Tracy, William Powell, Clifton Webb and numerous other co-stars.
Loy's steady and dependable acting allowed both Shirley and Cary Grant to be more expressive than the script indicates, making the movie a giant success and bringing Shirley's (adult) acting into the limelight once again. With this freedom, she could be herself and act. The result was a half million dollars for RKO and a runaway hit's publicity for Temple.
In "Baltimore" Shirley has no such attachments and no such freedom. There was no Myrna Loy to make her feel alive and open. The movie doesn't work well because there is little chemistry between the actors, even between Temple and her husband, John Agar, who did a good job with his role. A period piece was not something Temple needed. She was growing up and needed to be seen in the present day, as she was in "Bobbysoxer". Instead, and unfortunately, she is to go through several more scripts that do not fit her burgeoning character, and thus are movie flops, before finally calling it quits.
Shirley Temple had the acting skills to continue making movies, but she needed adult scripts and actors around her who were supportive, like Loy. It's a shame she hung up her shingle and simply quit. All she needed was the right "magic" around her.
