Launchpad isn't a separate world in OS X, it's just a way to see all your applications, it doesn't have active tiles that feed you information. It feels a part of the OS. Microsoft has tried to integrate the Start screen back into Windows 8.1, so it's less jarring, unfortunately Windows 8 apps still run in there own desktop full screen by default rather than allowing you to make them full screen like OS X. I think Microsoft tried too hard, instead of just copying OS X they tried to one better OS X and they aren't really good at that.
What needs to happen is that Windows 7 apps need to run in the Windows 8 desktop so that they can just do away with the Windows 7 desktop entirely. The tiles need to be rethought. Is it really necessary to display information in a program launch window? And while better they really need to think about how to switch between full screen and not full screen. They need to pull touch and non-touch apart and optimise for both.