here's a quick mock-up.
just saying, from a usability stand point OSX launchpad, and iPhone layout they work pretty well. Since the content should be dictate by the format.
It would also maximize the functionality of the screens real estate.
I like the Watch OS icons. It's perfect for a smaller screen.
I think they are trying to avoid it looking like a tiny iphone on your wrist.
I have a hunch that the reason the home page is laid out the way it is, and also the reason why the icons and a lot of elements are circular, is because apple plans on releasing a round apple watch in the future (like the moto360) and that the rectangular form factor of the the current apple watch is only a temporary design.
It might take a while, but once you know where all the apps are on the home screen, the existing layout will be significantly more fluid.