Ratner did a good job and, imho, he has gift us with some of the best action scenes of the original trilogy.
But the script was weak. Imho, the Prof X's death was ok, to me. It's an adaptation and it works but only if Scott was alive and he was the first "ally" that Jean killed, to show how powerful and dangerous was.
I believe, seriously, that the script is really weak or bad. I was hoping for a rewrite but, seriously...Dark Phoenix's saga is one of the best saga in X-Men's comics. Why mixed with Cure's storyline? Phoenix's saga have so much to tell alone for a movie!!!
If they did only Dark Phoenix's saga, with some changes (Cyclops survives, no Cure, much more development for characters likes Angel or Colussus) the movie surely was better.