strapped for cash:
"Yes but they should all be working at the behest or dare I say it, the direction of the director, no?"
Surely you have to acknowledge that this is not a constant from film to film? In principal, yes, the director's function is to organise various aspects of production; and as such, s/he usually plays a significant and shaping role in creative decisions. Some filmmakers take on more technical responsibilities than others, but ultimately most are reliant on the skills of different personnel to facilitate their wishes. Again, this introduces all kinds of variables and subtle personal/individual inflections that shape or alter the finished product.
Of course a director will express degrees of approval or disapproval with the finished product, but for budgetary reasons and time constraints (the influence of producers/studio financiers), there are also inevitably elements of compromise involved.
I certainly wouldn't deny any of that, and I wasn't attempting to suggest that the director has a physical hand in every aspect of the production, but it is his "vision" that he is attempting to put on screen and whilst he is reliant on the skills of others to deliver that, the film will look the way it does largely because of the decisions that the director has made. Whether the end result is exactly what he had in mind at the outset is another matter, obviously.
Sorry if this sounds pedantic, but people continually stressing that a film is "as the director intented" grates on me somewhat. If you look back to the Hollywood studio era (roughly from the 1910s to the 1960s), filmmaking was largely regarded as a producer's medium, with a factory line approach to production where the director (with a few exceptions like Hitchcock) was viewed as another technician and generally overlooked when films were marketed. Instead, the names of producers, stars, and the studios themselves (which had carefully constructed identities) were displayed most prominently on film posters and in newspaper and magazine advertisements, etc...
I wouldn't disagree with that either but certainly today the situation isn't quite the same. A certain other filmmaker on a recent thread is getting plenty of stick because of his continual re-releases which, whilst certainly a marketing opportunity are almost certainly due in part because of his ongoing obsession to present his films as he always intended them to look in his head. Granted in that case he's also the producer but I think the point stands. Cameron certainly isn't alone in wanting to re-outfit his products as advances in technology allow.