People seem quite caught up in their desire for this movie to match the visual look of the OT. In some things, I agree. The universe should look lived in; things like flashbacks or dream sequences should stay out of it; the colours should look right; it shouldn't be a two hour-long, action-packed frenzy of eye-candy, but it should have it's moments like that. But when it comes to moving cameras and the like, or visually packed sequences, why should it be like a movie made 40 years ago? I expect, with the newer technology available, that this will be done, because the technology exists for it. Regarding busy visuals, what about the RotJ space battle, particularly the shot of oncoming TIE Fighters? I bet there would have been more business if it had been more practicable. Additionally, it seems to only be the action scenes that have this business. That's what I want to see during action.
As for people's expectations: keep in mind that your expectations are almost certainly higher than they were in 1977, '80, and '83. Were you scrutinizing the movies this closely and critically back then? Now, after improvements in technology in the movie industry, and the numerous other ideas that have been used and reused, making it far harder to be original, people tend to be more critical and cynical about movies. Don't go into the movie expecting to see the OT again, or even hoping to. The OT was classic, but the ST will not be classic, for several reasons: it's continuing a classic saga 40 years after the fact, and will necessarily be different in many respects. It just will not be the same, no matter how much anyone wants it to be. Due to cultural reasons and higher expectations than in the '70s and '80s, it will be harder to enjoy the movies as much. We can hope that it will reflect the OT as much as possible, but it will not become a classic itself, even if it's good.
The ST will be a trilogy of it's time, as the OT was. The OT looks like it was made in the '70s-'80s, and the ST will look like it was made in the 2010s. The story will not likely be completely original, because so many potential storylines have been used, leaving less ability to be original. If you analyze the OT to bits, it doesn't seem so good anymore (it only seems to still be amazing out of nostalgia and the memory of it being as enjoyable as it was), so don't analyze this trilogy or the trailers too much. Sit back, don't pick it to pieces, and enjoy it for what it is.