Only if THE LIZARD is the main villain, should Sam Raimi return to do SM4 with the same cast. If not, then a new director should take the helm, along with a new cast. There is nothing wrong with finding new blood to write, direct or star in a Spider-Man film, as long as they take your time to find the right people.
I would also like to see new writers working on SM4, regardless of whether Raimi is still the director. New blood is needed no matter what. I'd like to see Sony hire writer(s) outside of the previous films. This means no David Koepp, Alvin Sargent, Alfred Gough & Miles Millar, Sam Raimi, Ivan Raimi, etc.
If there's no new blood in the writing department, then maybe it's best for a new director to come in, and shake things up in all departments for the better.