These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: The Dark Phoenix Saga
Big Lipped Alligator Moment: Dazzler's introduction during the first third of the arc feels jarringly out-of-place. She made up for it in later appearances, but in the context of this story she's very much this.
John Byrne's artistic contributions can't be discounted either. His art was at turns incredibly complex and deeply evocative; the book is still held up as a standard for superhero comics today thanks to their collaboration.
This story became the standard against which all X-Men arcs are judged, and has been retold and revisited in almost every media. Sometimes, it's the only reason a creative team will even put Jean Grey in an X-Men story to begin with. It's been a good decade since the last screen adaptation to not treat it like the only story she was ever in.