I'm not trying to sell anyone on anything. I couldn't care less if anyone else uses an S-view case. I love mine. Other people should get something they like.
You (I assume you are the same person under another username) asked for an explanation and I gave you one. And no, what you suggest is not practical at all. If the picture view was proportional to the whole screen and made to fit into the s-view window, the resulting rectangle would be so small as to not be able to see if it anything was in focus. I'm just using common sense here, no need to sell anything.
I have one as well, and I do like it for the most part. I'm using common sense as well. The rectangle is big enough to be able to view exactly what you need to take a good picture. I have a Flip Camera with a slightly smaller screen that you can see perfectly what your recording, I also have a gopro4 silver with the touchscreen, this time much smaller then the rectangle on the s-view that I can see perfectly what kind of picture I will be taking. These are just two examples, keep in mind that you are just using the screen to line up the picture, you can always view it in it's entirety by opening up the phone. Hell, the previous versions of the gopro didn't even have a screen and people still managed to take the pictures they wanted.
But fair enough, I can see that you like the extremely cropped pictures and that works for you, I personally don't. My argument was simply that it will come down to a matter of what you are ok with, not the fact that the s-views hole is too small, because it really isn't.