Depending on how far along you are, you would need to remove trim, drywall, electrical and plumbing (if there is any in the affected wall), re-do the framing, installing the Johnson hardware (use only Johnson) and then re-do the drywall, paint and trim. It sounds like a lot, but it really isn't unless there is plumbing or electrical involved (which there shouldn't be if a pocket was planned for the space). It shouldn't matter to you how much work it is. The builder screwed up, he fixes it. That said, why was this not caught long before there was drywall? I assume the pocket door was marked on the plan? And yes, it is worth it. A pocket door was likely put in because it made the most sense for the space (that is why I have the two I have).