Emphasize to Excel
A good program is a balanced program, right? It's sounds sensible, but it's actually not true. A good workout plan isn't about balance. It's about addressing individual needs and helping you reach your particular goals.
You will excel in what you emphasize. So your training program should be imbalanced to some degree in order for you to dedicate more overall training to the areas you're trying to develop most.
Research shows that there's a dose-response to gains in muscle size and strength. So it's a mistake to have a "balanced" training program that dedicates roughly the same amount of exercises, total sets/reps, and training days to your weaker, less developed areas as it does to your stronger, more well-developed muscle groups.
Now, if your goal is to be proficient at a little of everything, but not to excel in any one particular thing, then balance may just be the best thing for you. But not for everyone.