Arguably the biggest hardware leap so far was the 3gs -> 4, and that was limited to an aesthetic re-envisioning, a camera improvement, screen resolution upgrade, and processor bump.
This design showcases improvements that Apple would likely spread out over 3 generations: everything listed for their biggest leap above, plus new input mechanisms, new connector, significantly less heft, and waterproofing (!!).
Don't get me wrong -- I'd buy this in an instant, but it looks more like iPhone 8, than 6.