To be honest it's hard to see right now since Apple has done some cool stuff with that dual camera and it's continuous improvement over Microsoft's hobby mentality.
iOS does not have any feature that compares to Continuum. What it does have though is integration with Mac OS through its Continuity and Handoff features, which are not the same, but are still a force to be reckoned with.
Sure. They need to get back to those glory days when they invented the smartphone, multitasking, the portable digital music player and... the personal computer...