The Redhawk uses a single spring in the action unlike the later Super Redhawk which uses the traditional two springs. The Redhawk frame is a little difficult to get a good feeling trigger because decreasing the trigger pull also impacts the trigger return. The Redhawk also has a traditional grip frame whereas the SRH has a grip frame stud. I own both, and I prefer the SRH action and grip frame.
I really like the older factory grips that Ruger offered on the GP-100, SRH, and SP-101, and those grips were made possible by the grip frame stud. I, like many others, would love a SRH grip frame and action on a standard Redhawk (no frame extension) gun. It would be the best of both guns.