The U-shaped palatal major connector is designed to avoid crossing the median palatal raphe, making it useful in certain clinical situations. However, its narrower and less rigid design results in increased flexibility compared to other palatal connectors like the complete palatal strap. This flexibility can compromise the stability and support of the removable partial denture, leading to potential movement during function. Therefore, the primary disadvantage is its flexibility, which may affect the prosthesis' longevity and patient comfort.

Reference: Prosthodontics, Thomas J. Connell, 3rd Edition.