While Disney declared the Star Wars Expanded Universe (EU) non-canon when they purchased the franchise in 2013, the stories still inspire the Star Wars lore. I grew up with knowledge of the Expanded Universe via Wookiepedia and ventured to reading some of the material. Some of the best characters came from the EU and would have made excellent additions to the new Disney canon. Here are a list of some of my favorite EU characters.
1. Mara Jade
Mara Jade is one of the most interesting characters to be introduced into the Star Wars universe. First, she started off as the Emperor's Hand—which was basically another one of Palpatine's workers. She wasn't his righthand man like Vader, but Mara Jade did carry out certain tasks for Palpatine, including, of course, murder.
But that's not what made Mara such an interesting character; it's her backstory. Before she had her place, a life, working for the Emperor in the shadows. But she lost all that after the destruction of the Empire. Her former life destroyed, she went rogue—but promised herself to kill the man responsible for ruining her life: Luke Skywalker. Five years later, in the "Heir To The Empire" novel, she's working with smuggler Talon Karrde, and together they manage to capture Luke. Somewhere along the lines of the novel, she and Luke end up having to work together, where she eventually reveals her disdain for Luke. This is the moment that just reinforced the idea that she's an awesome character.
Besides all of the awesome stuff I mentioned about Mara earlier, she's got one other major bonus: she's one of the few female characters who has been a Jedi (eventually) or just wielded a lightsaber—either on the light or dark side of the Force. As a The Thrawn Trilogy writer, Timothy Zahn, said that he wanted to see more interesting women in the Star Wars universe, which prompted him to write Mara Jade, and I approve of his very successful efforts.
2. Darth Revan
When I first played the Knights of The Old Republic series, I immediately fell in love with the series. The characters were just many of the facets that made the game so intriguing. There was one in particular who intrigued me the most, and that was Darth Revan.
He was such a complex character. I love how he redeemed himself without giving a villain-redemption-sacrifice sort of thing. It would have been fine and all, but not everyone has to redeem himself that way.
3. Jacen Solo
With Jacen, I didn't so much understand his reasoning for turning, butt I loved the irony of yet another Skywalker turning to the dark side. Many Skywalkers have turned to the dark side or have been tempted (Anakin, Luke, Luke's son, Ben, Leia's children Jania and Anakin). The galaxy would be a less interesting place without the Skywalkers.
4. Siri Tachi
I love the idea of a female Jedi, so I was automatically on board with Siri Tachi's character. Disney has improved things, but in the past Star Wars had too few female characters. I love the way she carries herself, her feistiness and spunk. She does try to be the epitome of a perfect Jedi by following the rules, but she does so in a stubborn way. I have a feeling Duchess Satine from The Clone Wars seres was inspired at least somewhat by Siri Tachi; not only did she have the same fieriness (and blonde hair), she was romantically involved with Obi-Wan Kenobi, though there interactions were contentious on multiple occasions. But she was her own person first and full-most; her relationship with Obi-Wan was just a bonus.
There are plenty of awesome characters from the Star Wars universe I'd love to see incorporated in canon. I'd love to hear anyone else's thoughts on their favorite Expanded Universe characters and why.