The rumours for the as of yet unannounced iPhone Edition / Pro seem to suggest that it will feature a 5.8″ 2800 x 1242px screen.
Using a bit of trigonometry, widescreen videos on this unannounced iPhone Edition / Pro will only be 104% the size of the regular iPhone 7, whereas the 5.5″ screen on the current iPhone 7 plus displays a video 137% the size of the regular iPhone 7. This can be seen graphically below.
This may be a huge issue for me, as I use my iPhone 7 plus a lot to watch YouTube.
