Is this your book?
http://tolkiengateway.net/wiki/Mordor_%28book%29
The new book features:
1. the updated warband rules for
LotR SBG. This is identical to the information in the other four 2012 faction sourcebooks. It includes their six generic scenarios to play.
2. the stats and rules for all the Mordor models. I don't *think* there are any
LotR Mordor models that aren't included, though I can't be sure
3. five thematic scenarios that include the book's faction. Some of these are nearly identical to ones in the three Lord of the Rings story sourcebooks, and some cover events that are in those but differently.
4. a table at the back of the book with a stats summary.
I'm not sure what models may be included in it that aren't in the 2007 book. The "named" Ringwraiths are in it. So is the Great Beast of Gorgoroth.
So, in summary the new book has the warband rules and competitive scenarios, the most up to date model rules that should cover the entire Mordor faction as released, and five story scenarios. It does not include anything else that may have been in the 2007 book, such as painting or hobby guides or what have you.