This is where I reveal the extent of my Star Wars nerdiness.
When I was a kid, I used to read movie novelizations, including all the Star Wars-related movie novels as well as the non-canonical* novels, like Alan Dean Foster's still-beloved Splinter of the Mind's Eye, which takes place between "Star Wars" and "The Empire Strikes Back," but features a Luke/Vader encounter that really doesn't go well for Vader (in fact, "Empire" features nearly the opposite outcome).
Later in life, just when I thought I had buried my nerdish tendencies for good, along came Timothy Zahn with a new trilogy of Star Wars novels: Heir to the Empire, Dark Force Rising, and The Last Command. These stories take place a few years after "Return of the Jedi": the New Republic is in the process of mopping up remnants of the Empire, but one of those remnants, Grand Admiral Thrawn, proves to be a threat to the existence of the fragile new order. Han and Leia are married and have twins: Jacen and Jaina. Luke remains single, but little does he know that there's a potential love interest on the horizon: Mara Jade, also known as The Emperor's Hand—a secret assassin who operated in the shadows during the Empire's heyday, independent even of Palpatine's more visible right-hand man, Darth Vader.
I'm all for strong female characters, but not when they're obviously the author's pet creation, so cherished by the author that he gives someone like Jade pride of place even over Luke Skywalker. By the time we get to the climax of The Last Command, the final book in Zahn's trilogy, Luke is reduced to near-uselessness while Mara Jade steals the show and performs all the heroics. That was a highly disappointing conclusion to an otherwise diverting series.
Mara Jade doesn't become Luke's love interest until much later: Jade's character is taken up by different authors in the non-canonical universe, and she's slowly turned into Luke Skywalker's other half: she already has a limited range of Jedi skills, including a certain level of Force-sensitivity; add to that her native toughness, and she's a natural complement for Luke, who's been fairly lonely throughout most of these stories, having lived the hard life of a warrior-monk for so long. (Luke's arc is that he eventually founds a Jedi academy in an attempt to restore the old Jedi Order. Since he's ignorant of most of the Order's 1,000-generation history, he gets help from a device with massive storage capacity called the Jedi Holocron, i.e., a holographic chronology of the Jedi, with data and video footage from ancient to more recent times.)
In any event, I'm not a big fan of new characters' stealing the spotlight from the old ones. I don't know how much JJ Abrams plans to borrow from the "Expanded Universe," but I sincerely hope he stays away from Mara Jade. I might not mind so much if he creates his own original Star Wars characters—but as I felt with Timothy Zahn, I don't want Abrams's characters to crowd all our old favorites into a back seat.
Please, Mr. Abrams: no Mara Jade. For the love of the Force, no.
*Among true geeks, the term "EU," or "Expanded Universe," is used to denote all the stories that take place outside the context of the two George Lucas film trilogies. Perhaps my favorite EU novel is The Courtship of Princess Leia by Dave Wolverton. It's funny (See Threepio has never been more hilarious), and it respects the power of the Jedi in a way that Timothy Zahn's novels don't.