I have read hundreds of Expanded Universe books and comics, I was like the wookiepedia of the whole thing till 2014. And I have to admit that I'm so glad of the whole thing converted into Legends, actually it was EU who ruined Star Wars; so many absurd stories were born and a huge portions of the fanboys including me were so uncomfortable and disturbed with the direction EU was heading.
So Disney's wipe out move was indeed a correct, necessary one.
And you can include some former games into this category too. Let's take Galen Marek for example. A kid who's created for a game called Force Unleashed, is more powerful in everyway than Anakin/Vader, the Chosen One. Starkiller kicked Vader's butt in every single fight in both TFU1 and TFU2. A major part of Star Wars is all about Skywalker legacy, how can you just create a character for a game and let him mock Vader like that? That was a disaster. I'm so glad that it's just a Legends content now.
It's George Lucas' fault that he simply blessed every single author to who wanted to write a novel inside his universe. He didn't have any spites against them at all, otherwise he would avoid letting them abuse his creation like that. So he had to fix those ridiculous stuff, I'm sorry.
If he could only be more selective about those authors.
I see your concern about Mandalorians, but if you check their page in Star Wars wiki, you'll see that they still preserve some very cool stuff about their prestige.
The new canon lore is much more interesting now, aı love it much more than the extremely absurd and bloated EU.