"LucasArts was an amazing partner on LEGO Star Wars II, and working with them on The Complete Saga continues to be a great experience," said Tom Stone, director at TT Games. "We're also thrilled to be focusing on next-generation consoles and creating content that plays to the strength of each system." 

From the Trade Federation's "negotiations" with Obi-Wan Kenobi and Qui-Gon Jinn in The Phantom Menace to the space battle above Endor in Return of the Jedi, The Complete Saga allows players to kick some brick through 36 Story Mode levels, including Episode II's newly added high-speed pursuit of bounty hunter Zam Wessell. Traveller's Tales has revamped levels from the original LEGO Star Wars to match the gameplay evolutions found in LEGO Star Wars II, and Prequel Trilogy characters can now be mixed and matched with those from the Original Trilogy - more than 160 in all.

Apart from DS owners, it is hard to see what might encourage the hard-core Lego or Star Wars fan who already own the two original games to buy this edition.  Still fanatics are a hard group to pin down when it comes to their favourite subjects.
For the record, Page 2 gives the details on LucasArts' reasons to get into the new release