When the first Aftermath book came out it was received fairly poorly, whether because fans had expected more Luke, Han, and Leia than was given or because Wendig's unconventional writing style turned people off is debatable. When I finally got around to reading it, with the intent of binge-reading all three books back-to-back I was surprised by how much I enjoyed the new cast of characters.
Jas Emari and Sinjir Rath Velus are two of the best additions to Star Wars Canon. They both fit perfectly among the likes of Thane Kyrell and Ciena Ree from Lost Stars as characters that could have a long life span in this universe. Jas's arc from cold-blooded bounty hunter, to valuable member of the team is reminiscent of Han's transition from smuggler-scoundrel to hero-scoundrel. Sinjir's arc is more about putting his dark past as a Loyalty Officer behind him. While I was initially unsure about Wendig focusing on a romance arc in the third book, it ended up paying off nicely in an emotional display of growth for the sarcastic drunk.
The main character, Norra Wexley, has an interesting arc from being a concerned mother to a revenge driven fighter on the desert world of Jakku. It made her go from a fairly bland character to a more fascinating one. Her son, however I have mixed feelings about. It's tough to separate his age with his decision making. By the end he's largely learned from his mistakes, and brings a dash of youthful ignorance to the team that makes sense, it's just occasionally grating. His droid however, is awesome. He turned a battle droid from The Clone Wars into a badass killing machine HK-47 would have been proud of, named Mr Bones. There's even a reference to Revan's faithful murder droid that had me cheering.
In fact the moments that did included Han and Leia felt a tad forced and out of character for me, especially in Life Debt where they have a larger role. Empire's End though corrects those mistakes and Wendig really nails their voices, especially Han's, in a way that I got a tad misty eyed by the end.
Poor Wedge had a chance to really shine as more than a supporting character from the movies, but in the end he's relegated to being: a plot device in Aftermath, a love interest that's abruptly sidelined in the second half of Life Debt, and an afterthought in Empire's End.
In contrast, a character that has a small role in Aftermath and a larger role in Life Debt is Jom Barell. His inclusion on the team came completely out of left field when he joins the "Emipre Hunters" at the end of Aftermath. It's not until he returns in Empire's End that I realized how he'd been a vital piece of the crew. His relationship with Jas is both head scratching and heartbreaking by the time the third book ends. I think it worked to great affect because he was always an outsider tot he team and it felt like we barely got to know him before his untimely sacrifice.
Which brings me to The Battle of Jakku. Jakku is as much an integral character to this world as any of the sentient characters. Wendig takes the sandy cousin of Tatooine and gives it a grit and history that deepens Rey's scenes in Force Awakens. I don't mean he reveals any plot points for her character. I mean he shows how deadly the planet is, whether it's the dehydration, the scavengers, or the local Hutt that gave the outpost its nickname.
I think the most important bit is the formation of the First Order. After Counselor Gallius Rax put the Empire in a position to be destroyed, Rae Sloane, Armitage Hux, and his father set sail for The Unknown Regions. It's likely here that they meet Snoke. Which opens up a bevy of theories that hadn't been fully considered for his backstory.
Overall, The Aftermath Trilogy for me was a positive experience. It's not perfect, and may change based on your expectations, but it's pulled the curtain slightly back on the mysterious post-Return of the Jedi era of Star Wars.