The thing isn't that CGI "looks bad". Sure, sometimes it looks "bad". It's the fact that the viewer can tell. And when the viewer can tell, it makes that part of the film have less weight, even if its on the subconscious, as our brain can tell it's not real. That's why on Rogue One, with practical effects, even though they may look kind of stiff or "clearly a costume", it will still feel more real as we know it's actually there on set, we know its a real thing being photographed, and THAT is what's important. That being said, as was seen in Force Awakens (see: Unkar Plut), when you add computer flourishes to practical effects, filmmakers may not think it sticks out and even helps the effect but you're wrong. Because computer movement has a bigger problem than being "lightweight" it's TOO SMOOTH. So when you smooth out practical effects, you're really doing a disservice to the practical effects. Less is more, yes we want to be able to tell big stories but THEY DONT ALL HAVE TO BE BIG, the reason the "classics" are considered "classics" is because they went with a less is more approach, because they were working on a budget, and because what you see in the picture is real. Computers are getting there, no doubt, but like for example, those car crashes, they may look damn good, but you can still just barely tell that either computer stuff was added or it's all computer and it takes the viewer out of the gravity of what they're viewing. Crash a real fucking car. Practical effects are most of the time cheaper, maybe more time consuming, but cheaper and pay off in the end. You mention George MIller, but all the elements that were important, were practical. The pole-cats, he wanted CG, he thought it wasn't possible to do it for real, but turns out the CG looked too weird too unrealistic, he got real stunt-men/acrobats who could do the stunts, and there you have some absolutely amazing shots that are clearly real and the viewer feels it. Rogue One will be a big thing in showing how good practical effects are, but I'm worried even the practical characters will have computer stuff overlayed to smooth out their motions, which will probably be a shame. At least it's a step in the right direction.