The one thing which the iWatch must have is the ability to function *on it's own*. If it 'needs' to be paired up with an iPhone in order to be useful, it's completely dead in the water and useless.
The iWatch should be simple: display time, date, fitness apps and music. It shouldn't need to be fed data from an iPhone to look at messages or texts.
It should also have a headphone jack, it shouldn't rely on bluetooth audio.