So with "too repetitive of A New Hope" as a popular talking point, let me expand on one line of questioning. When can a classic be sufficiently classic to allow for repetition and reimagination? Romeo and Juliet becomes Baz Lurhman's Romeo + Juliet and West Side Story. Pride and Prejudice becomes Bride and Prejudice (in addition to just being Pride and Prejudice about 20 times). Same goes for much of Shakespeare, Austen, Bronte, Dickens, etc. Is it okay so long as it is going across media?
I don't see a re-adaptation as being the same thing, since in continuity that story and the original story didn't
both happen. I also think you are correct that being a cross-medium adaptation gives more leeway, since the process inherently allows for more interpretation than a direct movie-to-movie remake.
The key place where simplicity hurt is with the first use of the weapon on the Republic. I'm not sure they make clear what is being destroyed. Is it just some of the Republic, is it the very heart of the Republic, basically destroying it as a political establishment? Either way, I don't have a good grasp of who the people of the Republic or those planets were. I can obviously grasp that it is horrific, but it is fairly weightless for the deaths of millions or billions of people. Contrast that to the threatened second use, which was a clear existential threat to the Rebellion, but that seems to be like a few hundred people. It just happens they are the people we know and care about. Shouldn't I mourn the death of a billion more than fear the death of a thousand?
This is the kind of thing I mean when I say "shallow rehash". In A New Hope, we had context and a reason to care about Alderaan. You felt the significance. I honestly don't even know what planets blew up in TFA. I don't think they told us, and nobody seemed to care. For that matter I don't have any sort of understanding of the relationship between the Republic and the Resistance. Or even how the First Order plays into it all, where they came from, or why they have all of the Empire's tech. I find it remarkable how much lack of clarity there is despite taking the structure from a movie that is so clear about these things.
I think it's different if you already know there is a trilogy in place. With that in mind, I don't think any of them need to be "self-contained" movies, as they are part of a larger trilogy. When Lucas developed the idea for Star Wars, he said it was three separate stories which he broke into three separate trilogies. I believe this third trilogy is different than what he originally had planned back in the 70s, but the concept of a single story across the trilogy I imagine holds true. Unless you'd rather they give us a single, 7 hour movie instead of a trilogy...
My concern is that the next movie is going to have to spend a bunch of time doing the groundwork that this one skipped over. Traditionally you would have the first movie in the trilogy set up the foundation for the next two, but I don't think TFA did that very well. As first chapters, both ANH and TPM give you a much more complete understanding of their respective universes.