It should be noted that though Sarris, by popularizing auteur theory, might bear some responsibility for the current practice of assuming that the author of every movie is the director, he never fell into that trap. Sarris's criticism was more sophisticated and sensible than that. Auteurs were, for him, more the exception than the rule and he was quite capable of praising a film like Casablanca while admitting that it broke his critical framework. (Putting him one up on Dwight McDonald who often forced the data to fit the model, but more on that later.)
Directors are the most over and under-rated artists. Over-rated because they get credit for all sorts of things they have little or nothing to do with. Under-rated because most of their actual work goes unnoticed. As Kael puts it on Trash, Art and the Movies:
I don’t mean to suggest that there is not such a thing as movie technique or that craftsmanship doesn’t contribute to the pleasures of movies, but simply that most audiences, if they enjoy the acting and the “story” or the theme or the funny lines, don’t notice or care about how well or how badly the movie is made, and because they don’t care, a hit makes a director a “genius” and everybody talks about his brilliant technique (i.e., the technique of grabbing an audience).That's OK for the audience. Unfortunately most critics function on the same level. When Sarris and Kael talked about the direction of a film, they actually meant the direction of the film. This was one of the things that made their exchanges so memorable.
Roger Ebert (a friend of both critics) has an appreciation of Sarris here.
For an example of great direction working with other elements to create a great movie, click here. For great direction in a not-very-good movie, click here.