Spielberg used to be a director that could sell off name alone, but I wouldn't say he is anymore. The quality of films he makes these days are nowhere near the classics he used to. In the past 10 years, the only movie he's made that was really well received was Lincoln. Prior to that he had ET, Schindler's List, Jurassic Park, Jaws, Munich, Saving Private Ryan, Minority Report, and my personal favorite: the Indiana Jones series.

I would also remove Cameron from that list. Not that he's not a very successful director, but he has literally only made one film since 1997. We'll see how Avatar 2-5 are received.

I would also keep an eye on James Gunn, although he's not really brining original ideas to life. That said, Guardians might as well have been original, since the property was virtually unknown before he came along.