Starting strength is a great program for learning the basic barbell lifts, establishing a base of coordination and mobility, and building some newbie-gainz LBM in one's first 6-9 months of training. But Rippetoe's training philosophy for what you should do afterword just falls completely flat on its face. Nobody has ever done well in powerlifting or in bodybuilding training like rippetoe advocates for his arbitrarily designated "intermediate" and "advanced" lifters. And like you said, developing muscular imbalances is practically a certainty if you train this way for a long time; noodle arms, non existent delts, and massive glutes and hamstrings. That might be fine for a kid benching 185x5x3 or whatever, but as you get stronger those muscular imbalances will start to matter a lot, even if your main goal is strength.