But then why did it suck as an origin movie, why then did the characters feel not as true and raw as they should have. The acting was superb, yet the writing felt empty. I felt the movie was rushed and they didn't really delve into the characters soul like they should have.

If it is origin movie you need to explore the character's soul and I find what introspection they did was lacking.

Charles Xavier at the heart of him has three main character traits. He is a dreamer, he believes he can heal the world, and he has a natural empathy with people. They didn't really deal with the first two problems with Charles in the last ten years his dream has been crushed and he has made the problem worse he made a school where he could help people but in the process he is responsible for the deaths of his students. What good has he done his students

His best friend, Magneto his soul mate (his relationship may or may not have been sexual) has become a murder, killed the president, and given to his own devices would perform a genocide on humans.
His adopted sister Mystique/Raven has left him and disavowed him.
His first student Darwin was killed by other mutants. If he never met Charles would Banshee still be alive?
His most promising student Beast hids his mutation from other people and become a recluse like him, only taking care of the teacher (a role reversal since Beast was a student and is now the caregiver).
Angel, dragonfly lady mutant, has disavowed him and is now dead after being ambushed and killed in her sleep.
Banshee, was killed for being a mutant, ambushed and killed in his sleep. If he never met Charles would Banshee still be alive?
Havoc, to Charles is MIA sent to war without Havoc's choice because of the draft, possibly dead. He is later almost killed for being a mutant though this information may not be known to Charles.

So what good has Charles's dream done for the world, he only hurts the people he loves and cares for, he hasn't change it, the world has only gotten worse. He has hurt the world, and the world has hurt him. If he can't change the world, everything he touches turns to ash, he is incapable of making positive change (he can't even walk this will hurt his emotional self esteem even though rationally it shouldn't), and the world is so overwhelming overflowing his senses that he can't keep on doing it anymore. Of course he will turn to the serum, of course he will turn to booze, of course he will become a recluse.

While this is hinted in the movie they didn't do a good enough job showing it. They only showed him being overwhelmed via the world but to show Charles Xavier you need to show his Greatness, his godlike potential, and then show his fall, his humanity, his limitations, his mortality. You need to remind us that Charles Xavier is larger than life for he is not just a life he is a dream, a dream he will instill in all x-men, a dream that can heal the world.

Magneto is the opposite though and they could have done more to show that he lives in the world that is Promises Betrayed. While Charles Xavier is a Dreamer, Magneto is an abstract man who is beaten down via life a hundred times and has become bitter and traumatized via the world. Magneto is a man who could repair the world given the right history as a child and adult, he could figure out how to make the world better, to make bridges, railroads, electricity, he is so talented so visionary his thoughts become real. While Charles could heal the world with his vision, Magneto given the right inputs can make a new better world effortless. This is why his power is so vast, he can turn abstract thought into concrete reality, he can impose his will on the entire being of the planet.

Yet Magneto is damaged, he now sees this world as irredeemable, he still believes a new world is possible but he must become a god to save it. He must become a Shiva who will destroy the old world to allow the birth of a new one. If he does not kill the old, the baby will be strangled by the jealous brother.

Magneto vs Xavier is the cosmic battle between Shiva and Vishnu, Yin and Yang. Together they could change the world, but due to circumstance they must fight each other endlessly.

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Raven/Mystique is a survivor. She also has suffered the horrors of the world, she will always change, always adapt, always survive. She will do what is necessary to survive. She will not kill for fun or pleasure, nor will she burn the world to the ground, she just wants to live in peace.

I feel like the movie was half baked all the potential awesomeness is there, the raw ingredient are pristine, but what was achieved was undercooked. There needed to be more time for the writers to go over the script, and the director needed more vision on what he wanted to convey.

That or I felt I was sold the wrong product, I wanted a sports car but got a mini van. I wanted an X-men movie or I wanted an origins movie but I got a disastrous half made gloop of both. Like undercooked cake batter.