I'd say the ST had awful aliens, but then again I can't say I ever fell in love with any of the OT species either. I know I'll get a lot of hate for this, but I always felt that the movies were the weakest parts of Star Wars as a brand. The OT, if we're being honest, is a mishmash of all the things Lucas liked. He couldn't get the rights to Flash Gordon, so he created his own Pulp SyFy. He added things that were popular back then like Westerns and Samurai films, a lot of Dune, some Asimov, then some Eastern Mysticism, allusions to the events of his time, a ton of comics, and after filtering it all through a Tolkien-esque Fantasy lens, we got Star Wars. Its sources of inspiration were so many that you can say that it is a unique product at the end of the day. But to me, that also creates a problem of appeal. By that I mean what exactly is the appeal of Star Wars? Star Trek has the Utopian future going on, coupled with space exploration and philosophising. It's the SyFy take on Naval Adventure Novels like Hornblower and Aubey-Maturin. WH40K has its Grimdark Edge going on with a huge universe where anything goes. You self-insert as your preferred Space GrecoRoman Templar Soviet Werchmart and off you go. Going away from SF, LotR has its own feel, WarCraft too, basically my point is that you know what you're getting at with them. You're not going into Trek for ninja sorcerers and you don't go into 40K for feelgood stories about alien buddies going on adventures. But with SW, what is its "thing"?
Personally, I think it depends on the Era. And that's why you have OT and PT purists. The OT is a Fairy Tale set in Space. The Knight (Luke), his Magician Mentor (Ben), and his Rogue friends (Han & Chewie) go to rescue a Princess (Leia) from an Evil Lord (Vader) and stop the Eviler Lord (Emperor) from rulling the World (Galaxy). They go on various adventures, they beat him and that's it. The aesthetic there is 50s Pulp SyFy mixed with a Space take on the usual Fantasy tropes. Yoda and the Ewoks being based on anthropomorphic versions of animals, with one being the wise master and the others being the cuddly but fierce tribe, the planets that are just giant swamps or giant deserts or giant ice deserts, and so on and so forth. It's the usual Fantasy areas but expanded to whole planets. Add a feel of the American Frontier and that's basically your OT aesthetic. The PT was styled as a Space Opera and has more flair. The environments are more lush and vibrant, we see more planets with distinct cultures and architecture, the story itself is styled more like a Tragedy set in a Space version of the Renaissance than a Tolkien-inspired Fantasy world. The story tackles more themes and sideplots, and leaves room for more players. There are MCs, but there are more secondary characters who can have their own adventures. That's the short version of the core differences.
I grew up with the PT over the OT, and while I can say the latter are more competently made, and the former had more ambition, I can't say that I enjoy any of them as films. Aside from ROTS, I've watched every other SW only once. If SW was only the movies, I doubt I would've cared enough to still engage with it. Whatever I like came from the EU. The games, the comics, the ones who utilized the settings. And the answer is fairly simple. The budget and tech just wasn't there to pull off a proper Space Opera. In comics you can draw whole Armadas battling it out and generally do whatever you want. Movies restrain you. Having not grown up with the OT, and not particularly liking the genres it was inspired from (Western, Tolkien Fantasy, 50s Pulp SyFy, etc) I have no real fondness for it. I don't much care for the characters. The aesthetics don't grab me. But the EU built upon the world in every direction. More battles, more characters, more varied tales, more planets with their own identities and so on. The PT has a scope and thematical core that grabs me more, so while I find the movies less "solid" and the choices made questionable, I do prefer it. But even then, it's the EU that added all the flair that got me in.
The ST's problem is that it had neither a plan, nor a hook. It ripped off the EU, badly, and run on just nostalgia for the OT. And the thing is, SW is not like Trek where they more or less follow the same beats. OT purists dislike the PT for the same reason the PT purists dislike the OT; they're fundementally different beasts. SW is like a comic book universe. Just because one reads Avengers doesn't mean they'll like the X-Men. They exist in the same universe, they have a lot of similarities, but they're ultimately different. The themes, the genres, the aesthetics in their entirety. So when the ST came along the only ones who could ever like it were two groups. Those who grew up with the OT and would feel nostalgia to the rememberries, and the kids who would be exposed to SW for the first time. It did nothing new, it didn't have at least a coherent homage, it did it all wrong, basically. The one thing I'll give it is that it had nice designs. My problem with the OT is that it wasn't futuristic enough. I vastly prefer SyFy over Fantasy, so I always like seeing sleek and powerful machines. The ST had some nice worldbuilding in the sense of ships, clothes, locales and whatnot, but it wasn't anything groundbreaking, it just was closer to my sensibilities.
Generally, I'm fairly in the camp where the films are my least favourite aspect of the franchise. I've never felt the need to rewatch them, and I likely never will. I'm firmly a comics person. As for my relationship with the property now, I like it still, but it's more of a "oh, yeah, sure" case instead of obsessing over it. I'm in the proccess of watching TCW/Rebels, but that's mostly because my schedule is tight and 20 (mostly 10 with the 2.0x speed) minute episodes help me over 1-hour long dramas (of which I've watched all the prestige stuff so I'm done). And because of my hoarding. I'm keeping up with the new shows because it's 1 hour per week for about 2 months at a time, so it's not a huge investment. I'll buy the figures I want and they're my priority now. But there's no real investment. My interest comes and goes, sometimes it intensifies, sometimes it dies. And that's with all other stuff, really. These days I have culled a lot of pop culture. From the ones remaining I've reached the point where I like them on principle instead of execution. I like the core concepts, and ideas I come up with of how I'd do them, but I'm not madly interested in revisiting the same old stories. I've chosen to still engage with them, which means trying the new installments and buying the odd merch, but that's as far as it goes. My days of obsession are long before me.
At the end of the day, I think it's natural. Aside from the overabundance of entertainment and the reppetition of its contents today, you can only become obsessed with something as a kid, when you're young and careless and have lots of free time. As you grow up your tastes change and the act of wasting so much time on something so utterly useless starts bothering you. Lots of people maintain a guilty pleasure, so there's that. SW, ultimately is for 12 YOs. It's pretty tame, it has some nice morals, it's feel-good, and that's that. Some like it well into their 50s to choose it as their guilty pleasure. Some prefer the X-Men or Superman or whatever. But you can't really be a functional adult and still keep up with 20 different IPs; it's just not feasible. Ultimately, SW is a poperty for kids that Lucas used as a toy shop and milked for money. All the rest is schemantics.
I don't know about you, but I just cannot seem to pour any actual investment in these things anymore. Star Wars is such a huge, sprawling franchises that involves every medium that it becomes tedious to even try. It's even worse than comics. At least there all you need is a guide for the tie-ins. You start at the beginning and keep on going until it's over. A comic can be sped read. Books, shows, games, much less so. Honestly, when I'm done with TCW and the such a burden will lift off my chest. It's too much of a commitment to care about something as trivial and fluctuating in quality. A movie I can judge. Even if it's succesful and it spawns sequels and some tie-ins, it's still feasible. Wars & Trek have just too much content. Even 40K is more tame compared to them. I find that whatever investment I do have, comes directly from aesthetic choices and the idea of a character/story whose concept I rework in my mind and eventually prefer the illusion I've constructed.
Maybe it's because I'm not the target audience, when you get down to it. I like edge. It's where I find pure enjoyment. Not edge as in blood and guts, but more moral questions than just "gud guys vs bad guys". I read F4 mostly for Doom. I liked the X-Men over the Avengers because of the X-TREME designs and more unique stories. So I gravitate towards the Sith, and considering SW is not about them, as they exist merely to be evil foils and nothing more, my enjoyment of it has dropped. It's not as hardcore as I'd want my Magical Knights to be, which is why I find 40K more pleasing. Or Dune. I like Space Operas. Huge battles, epic scopes, politics, Royal Houses, and so on. But iWars also doesn't have the pure sci-fi exploration of Trek, that while having little edginess, scratches another itch of mine. I consume Wars for the Sith, period.
Maybe there are people out there who live and breathe Star Wars still, but I'm not one of them. I like it, and that's more than I can say for most IPs I've involved myself with, but I'm not thinking about it 24/7. I buy my dolly, I watch the new episode and that's it. It's more of a completionist mindset than anything else. I keep track of the Sith, because that's what SW is to me. The rest is worldbuilding.
Many of the best moments in the history of *cinema* were the results of unplanned happenstance and the OT itself, arguably the greatest trilogy of all time, still had *less* planning than the ST. It doesn't matter what reason the OT had less because it undeniably proved that the level of planning applied to those films was more than sufficient. So any attempts to then turn around and claim that the ST failed *because* it's more thorough planning than the OT was somehow *too little* is pure fallacy. 
