Having purchased the new RF book (link) and at Steve the wargamers request I've tried to identify the differences between the two versions of these Rapid Fire Books.
The two big differences are that the new book is in colour and with lots of nice pictures, and that the size of the units are much reduced. Typically they are 2-3 times smaller than in the previous book.
I believe these changes are as a result of last years big game as it would be apparent to anyone looking through the game photo's (link) that any ordinary wargamer or club could not easily muster the forces involved. The book scales the divisions down to strong brigades or Kampfgruppe, while maintaining them as reasonably balanced formations. What I mean by this is that not all the components of a formation are scaled equally, but the result gives a playable force.
The other improvement in the book is that it is clearer about the forces needed for the various operations/battles covered, but does not give exact scenario/set up details so it is more suited to a mini campaign game.