I want to point out that Miracast actually does support "smart" streaming a la Airplay. However, this is built into the casting device and not the receiver. For example, Samsung devices will push only the video and not the ui elements when playing back a video using hardware rendering - exactly how Airplay does it. You can change functions and seek and generally interact with the phone while the video is playing on the TV without affecting that picture. Furthermore, the video is only played on the TV while the phone displays only the ui elements and a black screen where the video would usually be. This works in any app that plays the video using the hardware decoders - the stock video player, mx player, even YouTube all function like this. Software rendered videos and games display everything including the ui as the article says.
Problem is, not every device/rom support this functionality. Samsung roms/devices support it, but most custom roms don't. This includes paranoid android, cyanogenmod, aokp, etc. These display exactly what you see on your device on the TV - just straight up dumb mirroring. I'm not sure what other manufacturers support this functionality since I only have Samsung devices.