I think James Cameron is probably the best commercial director working today (am I going to get lynched?). He can craft a story that appeals to the widest audience possible. That is the reason I think there's some James Cameron hate out there, especially for this movie. They recognize it's a commercial movie for the masses and they don't like it. Truthfully I could see how someone could watch this with that mindset and not like this film.

I argue though that while it certainly is commercial, it's painstakingly well done and an incredible achievement. You can't really fault Cameron's directing here and he gets great performances out of his actors. I think his one fault though is that his characters tend to be underdeveloped. I don't think he'll ever make a film that will be considered a character study, but I also think he realizes this. He knows what his weaknesses are and compensates for them with his strengths. I don't think you'll find a director that has more technical knowledge of his craft.

Note: Me thinking he's the best commercial director does not mean I think he's the best director out there.