Mentasm:
[There are many factors that affect the amount of grain in an image, not least of which are the film stock used and the lighting. Are you advocating that studios DNR the hell out of their films, thus eradicating visible grain and therefore removing image detail? Not all films are supposed to look like Pixar animation! Close Encounters is an accurate transfer, which is what Blu-ray is meant to provide.
I think to be honest most people expect all fims to look better than a pixar animation! HD is all about sharpness and visible detail. An accurate transfer is not really what people are looking for either. They're looking for a significant improvement over traditional DVD / tv / cinema footage (the last one makes sense when you consider screen size). However, DNR is not the answer.
I think there's a fundamental problem with many older films when it comes to making the transfer to BD. Whilst there's no doubt all films were shot at more than HD resolution there's more to sharpness than resolution. The sharpness is affected by the quality of the lens used (not all studios especially low budget ones have always been able to afford ultra high quality lenses and lenses have got better over the years), the film stock used - not all film is equal, the film speed used (any stills photographer will tell you the faster the film the more visible grain - it might be that a particular fim had a lot of dark scenes so they used faster stock, or maybe it was just cheaper so they bought a batch!), the lighting, the quality of the processing. There are a lot of factors.
You have to remember that with the very latest films being shot on ultra sharp digital cameras, older film can't always match that and even with modern cameras, there's still a difference according to lens and sensor quality.
That said, as Clare said, quality of transfer is very important. As the wizard of oz shows, if you have a good quality origianl and do a good quality transfer, then you can get a good result even with an old film.
I also think Home and Away on FIVE is a good example of how compression affects a programme. I've been watching it on Freesat and the transmission is so good I'm seeing things I've never seen in over 10 years of watching the soap - detail in Lea and Martha's faces, grain in the stonework in Roman's flat, I even saw a plant in the corridor I've never even noticed before. In fact for SD, I'd have to say it looks HD to me. It could be its now being shot on HD and downscaled to SD as this does produce better results than SD alone. However, the point I'm trying to make, is it blows the other SD programmes away for quality that I've seen and as they all transmitted in SD there can only be 1 difference - the quality of the compression (transfer if you like) on the original stock.