Spin stabilized satellites usually have nutation dampers to negate imbalances. You'd probably need them on your boom design, too. Given the long arm between the masses, you'd need the ability to maintain the proper axis of rotation as propellant is consumed. Vibration dampening would probably be a good idea, too.

Many years ago, I saw a news segment on a rather good idea for vibration dampening that involved piezoelectric ribbon. Piezoelectric ribbon generates a small electrical signal when stresses, or generates a stress when electicity is applied. The idea was to use the generated electriciy from a pzio strip on one side of a boom to generate a dampening force on the other side. In lab tests, it dampened vibrations in a flexible structure very quickly. I don't know if this was ever tested in space or if there would be material degradation issues, but it sure looked good at the time.

One difficulty with spinning structures is how do you handle required maneuvers like course corrections and attitude adjustments. Do you have to stop the spinning every time you need to maneuver? If not, then you'll have to use thruster pulsing. That tends to be less efficient in regards to propellant consumtion.