A visual effects shouldn't tell you that it is indeed an effect or seem artifical. CGI looks too clean or better too sterile. I guess it's how light is reflected on surfaces. A physical model looks real because reflections are natural and not rendered. It is like some informations get lost during rendering which than affects the overall look of the model. As long as you notice that an image is rendered with a computer the effect gets lost. That sequence with the falcon looks like a video game intro. That's not cinema or a good representation of reality. It looks fake. The mistake is in my opinion that the entire image is CGI. A good choice would be a physical model with some digital correction to improve the final result.
The TFA trailer Falcon looks the way we are used to CGI looking. But is that inaccurate, or just what we
think is the "CGI look"? I'm not sure.
I have seen some airshows and a few vehicle stunts & explosions being done live. More than once I have found myself thinking, "It almost looks like a CG effect!" Think about the implications of that. Maybe (the best) CGI work is closer to reality than we think but it fails to fit our mistaken expectations.
Do the X-wings in the TFA teaser flying over the water look better than the Falcon? I thought so at first. But maybe it's because they are something we can relate better to. Water, spray, moderate lighting, smaller ships that match our human expectations, etc.
The new Falcon is 1.5x the size of the OT Falcon exteriors. It would cover 2/3rds of a hockey rink now. The Falcon is not a fighter jet, it's more like an airliner that moves like a fighter. My point is that in most of the flying footage the ship is much bigger & farther away than we probably subconsciously assume.
Remember the popular still image from the trailer where the Falcon is just closing in on the blasting TIE fighters? The Falcon's engines are probably never less than 50-75 feet away from the camera in that "closeup". This is relevant because the image of the ship
should look "hazier" than we might think just because of that distance. There is also the effect of all the sand & dust being kicked up by the Falcon's engines in that whole scene.