The way Fastlane is featured in X or Ashs Series is pretty weird! I mean you will be having all your apps on start screen and for notifications, swipe right for Fastlane!!
I think that's poor way of app management. Now coming to WP, if they replace Notification Center with Fastlane, then how would they manage isolated listing of apps ??
Notification Center is pretty good in WP 8.1 and Seems promising.