11 added the tri-camera.

12 added the new flat side body, magsafe, 6.1” screen size upgrade, 5G in states.

13 added 120hz, 5G globally, ultra-wide lens.

14 added the largest camera upgrade since the 11, the first significant software/screen change since the X (dynamic island), and always-on-display

For me, losing the notch was the biggest thing I wanted since the X, and would consider it a big change year. I don’t see the 15 making any physical changes, and don’t think it will be a big year (imo)