I'm not a Star Wars fan (Episode 1 killed it for me), but watching this from the sideline has been nothing short of bizarre to me.
This leads to a faux or ironic nostalgia act by everyone involved: the "fans", the actual fans, the creators, and the media around it all.
It's making things pretty dull because this spans all ages. Older folks may have actually been fans from the start, but they still fall for teh nostalgia trip of the new media and spend money on it. And the media companies make things that are designed to appeal. To nod and wink at you for being so clever, for knowing which episode or comic issue that quote came from. For knowing that this guy was a villian in the comics, but here we'll give him to you as a bit part. Wink wink.
I agree with Red Letter Media's take on this: SW is fundamentally a small universe (yes the universe IN SW is vast, but the universe OF SW is not: it's just rebels+jedis fighting stormtroopers+darth-lords. The only attempt at expanding the universe, the prequels, was a disaster). With that in mind, it's not surprising the movies are so unimaginative and Disney keep repeating themselves.
My favorite example from the new Solo film: Solo is told something like "find me later on Tatooine".
Imagine somebody saying "If we get out this, see me later - I'll be on earth." Or, even "I'll in New York." Does Tatooine have more than one city? More than one bar? Is there a phone directory for finding people there?
The acting and direction I'll grant you, and yes, it's supposed to be a space cowboy western, but I don't think anyone would describe the sets or visual design of Star Wars as "Buck Rogers quality," if that's supposed to mean shoddy or inexpensive.
The one thing Star Wars gets consistently right in my opinion (even with the prequels, which I despise otherwise) is that it always looks good.
5. Carnage of Krell (Season 4)
4. Orders (Season 6)
3. ARC Troopers (Season 3)
2. The Lawless (Season 5)
1. The Wrong Jedi (Season 5)
Also, indoctrinate??? What are you on about?
Although there was no advance merch when Star Wars came out, this quickly changed when the toy manufacturing partners realized they had a real gravy train.
Legends was massive. The feats within Legends were sometimes outlandish, so it makes sense that it was all scrapped. The Plagueis meme was a throwaway line in a prequal movie. Luceno wrote the novel roughly 7 years later, and it is one of my favorite SW novels to date. It perfectly encapsulates the feeling of the Rule of Two, the Sith moving in the shadows to subvert an entire collective of governments, and the true power of patience.
Current canon isn't giving the universe enough room to breathe. They want to fill in every last detail on the timeline with no room for secondary or tertiary characters to have their own plot in the background. Plagueis was Sidious' master, but Luceno did not nor needed to fill in every last detail of Sidious' apprenticeship. We get some details of a young Palpatine, but the novel doesn't crash headfirst into the Phantom Menace.
TL;DR: Star Wars shined, because it always left room for interpretation and exploration - even in fleshed out novels.
Not the most original of the plots [1], but good enough and simple enough that most people can enjoy it. That's not the issue with the current state of Star Wars in my opinion. Also for most people Star Wars is the movies so the issue about what is canon and whats is not is moot [2]: for them it is canon if it appears in one of the trilogies.
I have three other different issues with the current trilogy (and in general Disney's approach to Star Wars).
The first is that the current trilogy is just more of the same. The Force Awakens to me looks more like a reboot of the original movie than a sequel. The Last Jedi is a bit better but only because it looks a reboot of the whole original trilogy: I think that a better name would have been "The Empire strikes the return of the last jedi", and that would even describe the most relevant parts of the movie perfectly. In a way the prequel trilogy is better: while it is not up to par with the original trilogy, I like the contrast between a world where Jedis are available by the dozen (for example see when the jedis come to save the main characters in the arena) versus a world where there are two "bad" force users (Darth Vader and the Emperor) and two "good" force users (Luke and, for a while, Ben Kenobi).
The second issue is more general, and it is related to the fact that regardless of the quality of the content, the more movies you make about a topic or a "universe" the less value the single movie has. Even worse, after a given threshold I won't even watch any movie about the genre because I fear that if I don't see all of them I will miss something. I feel that way about the gazillion of Marvel/DC Comics movies, I feel the same about Star Trek (I only know about the original serie, but I don't have time to see _all_ the episode that I missed) and I fear one day I will feel the same about Star Wars.
[1] Also it seems Star Wars got many idea from other movies. My favorite is the one about getting inspiration for R2D2 and C3PO from the main characters of Kurosawa's "the hidden fortress", though after seeing the movies I would say the resemblance is only in "the character of the characters"
[2] I have to admit that I played to some of the games, and I think that KOTOR has a story that is much better that Star Wars original story. THAT is something I would love to see a movie about.