What’s so sacreligious about it?
1. The fact that the protagonist is a girl (yes, it's true but she's written the same as Luke in ANH and no one complained about his upbringing.
2. Luke. Some see this cranky hermit and think he's been written horribly. Some see his past haunting him to where he doesn't want to help anymore. Mark Hamill mentioned he disagreed with how his character was written for the movie but still did it after speaking up and out over it.
3. The biggest, though, is that the new movies discarded everything that had been written for 20+ years to make the Extended Universe - and went their own path, throwing away that much written material. (Admittedly, some of the books were incredible, and some that are toilet paper quality.)
Personally, the plot was weak in some points, the film pacing made you think it was weeks on end - when it was really about 48 standard hours - hardly any time for the events to happen (such as travel via spaceship to the ass end of nowhere - and back) as well as two of the three primary characters being badly written.
My additonal complaint is the forced actions of the protagonist in a feeble attempt to save the villain which is a common lazy writing theme of "virgin good girl saves abusive bad guy with love" which is rubbish times twenty.
Add those things together and while it looks incredible, the story falls flat mostly.
I was entertained for it, even with overlooking some of the liberal themes foisted onto the movie (such as weapons dealing being a neutral thing 'cept for being utterly filthy rich; the slave kids; making another protagonist a hot headed fly boy who can't follow orders, etc.) and see how some things work, others don't.
I can't see how they can rescue the last one to make it spectacular - but merely entertaining.