What is the biggest problem of switching platforms? Is it the learning curve, the app discrepancies, or something else? In my opinion, it's the latter; but if a Microsoft patent filed in 2010 turns out to be for an actual, planned service, apps might not be much of an issue for people who switch to Redmond's operating system.
This patent is for a service that would allow you to essentially "migrate" your current apps to your new Windows Phone. There's an app that goes along with this service that will help you download the closest equivalent apps onto your new Windows Phone, and if there aren't any official apps or close equivalents, the service will notify you when something close enough is released.
The service could also be expanded to actually migrate app data to your new Windows Phone, although it would be a fairly difficult task for unrooted/non-jailbroken Android and iOS devices.
Regardless of the difficulty, this is a great idea. I'm still downloading apps onto my Galaxy Nexus to catch up to what I had on my iPhone. It would've been really nice to have a way to import or find all of my apps to my new phone.