This post has spoilers. Seriously, don't read unless you've seen the movie.
Now a barebones plot isn't necessarily something that dooms a movie. In fact the plot was the weakest part of Heir to the Empire, as I wrote on Friday. That books cobbled together a plot of various characters running from place to place before finding themselves in a small confrontation with the forces of the new bad guys, where they'd reach a bittersweet victory. It works in that book because the characters introduced are so strong, and even the small confrontations that occur have us on the edge of our seats with the heroes at a large disadvantage. The Force Awakens also has the new main characters running from place to place, but instead of winding up in a new plot, it winds up with the main characters re-enacting the original Star Wars near exactly (A New Hope).
It's always been a lazy tendency of Star Wars writers to try and make the stakes seem dramatic by adding a superweapon that the good guys need to eliminate, and TFA does that very same thing. And let's be honest, even the movie ITSELF realizes that it doesn't work, with Poe and Han basically saying that these things always have a weak spot they can attack in the briefing scene. Unlike Episode IV, which provides a foundation for its superweapon by having its existence be present throughout the entire movie (its what the good guys are trying to get R2 to Alderaan on in the first place!) or even Return of the Jedi, which starts out with the Death Star in the first scene and has the prior few movies to base the idea that the Empire would build another one on, in TFA, Starkiller Base has no foundation whatsoever. It's not introduced until halfway through the movie, destroys a few planets we know nothing about, and basically just provides a goal for the heroes to try to meet in the climax.
The movie's macguffin of the start, a map containing Luke Skywalker's location hidden inside BB-8 doesn't really work either other than to be a call back to A New Hope. Even if Luke has a reason for being in hiding, why is there a map showing where he is out there somewhere in the galaxy? Why would that exist? Fortunately, this is basically a macguffin that starts the plot and is of little significance.
Again, this movie does mostly work and IS a good Star Wars movie. The reason for that is, like Heir to the Empire, it does GREAT Character work. Fin, as the stormtrooper who rejects his purpose in favor of anything else, makes a great new hero. As I saw someone point out on twitter, here is a hero in Star Wars who wasn't chosen from birth or by blood to be impactful, but one who rejected his own purpose to do so instead. That's terrific! And the acting of John Boyega really conveys the character who wants to do right, but is scared and also just wants to get away from the Evil he has served his whole life. Rey, the girl from the Desert planet with a mysterious past but who both feels the call to adventure and who wants to return home to wait for her lost family is also great, although a bit of a mystery at this point. Poe Dameron is basically a combination of Wedge Antilles and Wes Janson, which is terrific (also ironic, given that a different Captain Antilles was the master of the Tantive IV in A New Hope).
The two villains also are very interesting - Kylo Ren, as the dark Jedi former son of Han and Leia, who wants to embrace the darkness but feels still the conflicts of the light, is a Dark Jedi of a type I can't recall in the EU - conflicted dark jedi in the EU tended to be ones who didn't really want to go Dark but used the Dark Side for their own good purposes, whereas Kylo does seem to want to use the Dark Side for some reason, which IS interesting! And again, it's nice to see a compelling villain who will show up in more than one movie, unlike in the prequels.
The killing of Han Solo also mostly works. The EU basically couldn't touch the main characters of the original trilogy, leading to them eventually killing CHEWBACCA because he was the one original trilogy character they thought fans wouldn't miss too much when they wanted to show things were for real. That was lame. Here, Han's death is earned and does make sense given what we learn about Kylo Ren. Of course, Han and Chewie enter this plot just out of nowhere (They're in a first order ship carrier some creatures for smuggling? And this just comes out of nowhere? Okay..)
Not all of the above works of course - Rey gets out of her imprisonment with a Jedi Mind Trick despite no training or reason to know to even try that. It's a fun thing for fans of the originals, but why would she even try that? There's no foundation given to it at all. Poe's escape from death is a clear hand-wave (and Abrams has said since that Poe did originally die in the crash) that makes no sense. Han being a smuggler again is...odd, at best.
But still, overall, the movie works - you get some fun action, some lightsaber battles (although Fin being able to wield a lightsaber even this well without the force is kind of meh), and good characters. That's Star Wars! The key question is whether they can build on this, or if they simply repeat the original trilogy further. Where the expanded universe tended to fail was when they tried to repeat the same plots over and over. Can they do a quiet soft scene in the next movie? Can they have a movie without another superweapon? Those are the questions for the future. Remember, they end this movie with Fin and Rey separated - presumably we'll follow both in the next movie. Can the next movie handle its protagonists separated? (Yeah it happens briefly in this one, but not in a major way).
Was this movie worth eliminating the Expanded Universe for? I'm not sure - again it's a good movie, but far from perfect. Still, the fact that my answer is "IDK" instead of "Hell no" is a pleasant surprise. I'm happy to look forward to finding out what happens next to see if I can give a more full answer.