The problem with the plainclothes era (IMHO), is that they didn't commit to it, and just did it halfway. They were kept in costume on the cover (for recognition), and half the time in the story they were switch back into uniforms anyway. And Robin didn't go "plainclothes" since he was probably still being used some in Batman/Detective and probably had some licensing reason.

Did that storyline actually get resolved, for was it just slowly forgotten and they just eventually were in costume full-time?