Holy cucumbers!!
Pre-rendered backgrounds are, as of this moment, officially obsolete.
Not really. If you have an use for them, you can just render out your background as an FMV (ala REmake) and then dump all the poly power into the player character that's superimposed over the background.
An interesting take though would be that if CryEngine 3 is easy to use like this, you can use it to make your backgrounds and then use it to render the character over the prerendered background.