The Samsung Galaxy A7 (2017) features a very large 5.7-inch display. The difference between 5.5-inch and 5.7-inch isn't significant. If we compare the Galaxy A7 2017 model to the A7 2016 model, the 2016 model has a 5.5" screen size and the same screen resolution of 1080x1920 pixels. Because both have the same resolution and the A7 2016 screen is smaller in size, it also has a higher pixel density than the A7 2017 model (401 ppi vs 386 ppi). Is it significant? not really and the visual quality is still going to be really good. Some think that screen in these sizes should go with 2K resolutions, but in my experience, a Full HD resolution looks great even on a 5.7" display. The only reason I personally would consider a higher resolution display is for playing VR games with my Google Cardboard. I also didn't hear about any support for The Galaxy A7 (2017) and Gear VR, which I believe is not being supports, because otherwise I would have read about it in the press release.
Here is an image that shows the relative screen size difference between the Samsung Galaxy A7 2017 model and the 2016 variation.
As you can see, not a big difference, but just slightly larger. Image via mobiledevicesize.com.