Graviton is more powerful than Megneto, and also, Graviton's power could create "Instant Death" for Magneto.
As Magneto is sending metal at Graviton through the air:
Hi Magneto! How would you like to instantaneously have a 5 ton head? No, not your entire body. Just your head. Great...
Scruunch...
End of fight.
Magnetism still needs ferrous materials, in order to function. Am I right?
And, anything that is effected by Magnetism must be made up of matter, which is made up of atoms.
Can't Graviton, theoretically, just send the different components that make up an atom, into different directions, basically causing the matter to cease to exist?
Graviton was created with total power over Gravity. Godlike power. Magneto did not have that kind of total control. And, to be honest, I think it is kind of cheap to have him be able to do whatever a writer thinks up during his run on a book.
He was created with limits, and barring him having a Cosmic Cube in his pocket or something, he should still have limits.
But, then again, that is typical of X-Characters. For some reason, the 'tards at Marvel think it is within continuity and plausability for characters, well past puberty, and some in thier later years in life, to continue to spontaneiously "eveolve" or "sprout" new powers, or higher levels of thier existing powers.
That just isn't how mutation exists. And, if they are going to use Nature's habit of mutating life into newer forms, and if they are going to follow most of the "rules" of mutation, they should also realize that after an animal, especially a mammal, passes puberty and reaches maturity, there is no new development.
These horrible characters should not be growing stronger and developing new powers into thier 40's, 50's, 60's and up.
It is stupid.