I don't know whether to be excited or happy about this because basically this is what EC has been waiting on his whole life. Included in RX8 by Izotope is a new plugin called spectral recovery and it guesstimates frequency that has been lost by compressing audio and adds it back into the file, it won't be perfect but it will slightly improve badly processed mp3s etc
there are examples of it working around the web
there are examples of it working around the web