Continuity is everything.
After Disney purchased Lucasfilm in 2012, a rather significant decision was made that split the fanbase. Thirty plus years of stories and lore in the Expanded Universe was wiped away and no longer considered Star Wars canon. The only things remaining were the movies, the Clone Wars tv series and a few scraps that were recently left over. Imagine the amount of time that people invested into the Expanded Universe only for it to be banished into legends and no longer considered canon. I can definitely understand why fans of the Expanded Universe would be upset by that decision but Lucasfilm and Disney absolutely made the right move.
My biggest personal gripe with the Expanded Universe was its level of continuity. I always felt like the Expanded Universe was just a collection of disconnected stories that came from anyone who wanted to write anything into the Star Wars universe. We had nonsense like Palpatine clones, dark side Luke and zombie stormtroopers flooding into the Star Wars universe just because someone wanted to inject their own fan fiction into the series, it didn’t matter if it made sense or not. While new ideas are important and we’ve certainly seen plenty in both the Expanded Universe and new canon, it’s also important that they’re not stupid. There was an absurd amount of inconsistencies throughout the Expanded Universe and it was practically impossible to follow. So Disney and Lucasfilm responded by taking the easiest route available to them; wipe it all away and start over with a clean slate.
In 2013, Lucasfilm created a team called the Lucasfilm Story Group, led by Pablo Hidalgo. With the help of Lucasfilm President Kathleen Kennedy, the group was formed for the sole purpose of maintaining continuity throughout the Star Wars series. Whenever a new story idea is brought up, the Lucasfilm Story Group’s job is to basically fact check everything and make sure that it not only makes sense within the universe but that is doesn’t contradict anything already established in the new canon. Starting from scratch has allowed Lucasfilm to steadily increase the Star Wars universe by building on top of itself and ensuring that continuity is maintained throughout the new stories. Now, Star Wars feels like one big connected universe where the stories all play into each other (to varying degrees).
Not everything from the Expanded Universe has been thrown away, either. While I didn’t personally like the Expanded Universe, it wasn’t entirely bad and there are many elements to it that are rather good. As the universe grows, Lucasfilm has brought back some of the better aspects of the Expanded Universe into similar roles in the new canon; like Grand Admiral Thrawn in Star Wars Rebels. We’ve also seen concepts from the Expanded Universe brought back and altered for the new canon (Kylo Ren). We’ll most certainly see this continue in the future with characters like Revan and it’s a perfectly reasonable compromise between the Expanded Universe and the new canon.
I’ve just recently purchased pretty much all of the new canon material and I’m currently making my way through it. Having only read a small amount of the books and comics so far, the continuity is easy to identify and hits you right on the nose. While there are still some aspects that I don’t necessarily like, it still feels like you’re reading content from the same series; not just jumping from one fanfic to the next. Now we can debate the quality of each entry to the universe but there’s one layer of foundation that remains; the level of continuity in the new Star Wars canon is way better than whatever the Expanded Universe was.