The PureMVC Framework Code at the Speed of Thought

I am porting a Flash project over to PureMVC. The project is a 'Memory' type game where the task is to match tiles in a grid.  Each Tile class really is a Mediator to a movie clip so I was inclined to set it up like the mediators in the sample PureMVC code. But I actually want Tile to inherit from a custom class rather than Mediator. After viewing the Framework source, it looks straight forward enough just have Tile implement IMediator.  But I was curious to see if there was a deeper reason to always extend Mediator that I wasn't noticing.

Thanks for the great project, PureMVC is now my homepage!