Let me explain a little. When you use NFC for sending files you only use it to connect Bluetooth or WiFi direct. NFC packet itself is very little to contain useful information. Android devices uses WiFi direct to transfer big files if both devices on same WiFi network, or switched to BT if not. Windows phone has support for WiFi direct but by some unknown reasons it works only between windows phone and windows 8 tablets. Tested by me a lot of times. But when you trying to send pictures, videos to android devices through NFC, it doesn't work. It seems that Samsung just enabled this functionality as they have full access to the system.
I know that applications from Microsoft and from vendors has full access to OS API, which is just closed to third party developers.
Vendors can even create file manager because they have full access to file system.
if Microsoft will ever open at least 20% of that api for us developers, world will receive tons of useful apps.