And non-plus screens all rotate. Zoomed and Rotation should be two seperate issues and functions. That Zoomed is only available 50%(?) of the time sure seems like a bug...or just lazy programming.
I got the Plus because I wanted the zoomed view, my 6s screen in a slightly larger view.
Still no warning about it when activating and Apple support never asked if I had Zoomed on, you'd think that would be the firsts question.