hmmm... I thought it was interesting. Of course, the movies have nothing to do with the books except that they are using the same ...sorta... characters...
Theoretically they do, of course, but the movie people do change book canon as they please ... soooo...
I thought the development of the character within the movieverse was logical... at least to a degree... and I LOVED that in the last scene, they gave him his "COLORS' as well as his name.
And I know the dictum came down that the book characters were to be kept as close to the movieverse as possible... some years ago, actually...I cannot see how that has changed since disney took over. Movies having a much larger audience than the books, it seems that now the tail is wagging the dog...
In regular canon, Magneto picked up his name somewhere between the Israeli -set backstory in Uncanny 161 which Chris and Dave did, and the first XMen number one, which Stan and Kirby did. 161 basically established Xavier's and Magneto's first meeting. The movies built on that, establishing Magneto as the co builder of the academy ... or at least Cerebro/a ... and the movies depiction of their friendship has been woven into canon... which is ok, since it covers years not depicted. .. and sort of enriches the characterization of the two characters and their relationship. It gives rise to speculation of who is controlling who ... or what... in this storyline.
I do think that they are leaning towards making Magneto a less sympathetic character but in reality, I have observed people walking out of all of the X movies saying "that magneto guy is right!!!" which is very interesting to me, LOL... as I concur.
My problem is... and has always been... that Professor X creeps me out and I do not think he is the angelic father figure he has been portrayed as in the books. They do explore this in the movies to a degree when they show him forcibly dampening Jean Grey's powers... and magneto objecting. I have always objected to the intrusion into the minds of the children on all fronts... especially in the early books. It was creepy. the only place a kid...especially a teenager... has that is really his or hers, is their minds. That's their sanctum sanctorum. And Xavier went willy nilly into them at any of his whims. We have only his word that he didn't violate their central thoughts... but those kids never acted like real teens. Teens are unruly, rebellious to many different degrees... some more some less. These kids were so freakin' well behaved it was pathetic. It bespeaks a mind control. Kids are cutting up as teens will do, ...?... noise level is rising... just a quick thought directing them back to quiet study...no harm no foul? well, to a degree...the wish of every parent of teens in the county, if not the world. I want a cup of tea but don't feel like wheeling down into the kitchen to get it... a quick thought to jean that"gee I bet the prof would like a cup of tea..." and bingo, no real harm... no foul? Where does no harm, no foul stop and a subtle slavery begin? and did the prof cross that line? I think he did... maybe not viciously, but he did anyway.
I used to have this discussion with dave ...often. He wanted to think of the prof as a good father figure... and I thought of him as a sneaky, albeit good intentioned, dictator. If you don't realize something is happening, does that make it not happening? No it does not. It just means the perp is getting away with it.
Now, Magneto, by virtue of his power, had to have some modicum of telepathy... after all, every single thing our bodies do or think is controlled by electromagnetic signals. But Mags control went to large fluxes, whereas Xavier's went to fine control of electromagnetic brain activity. Magneto controld HUGE power fluxes of the earth, and, as I explained to then X group editor, Bob Harass, the electromagnetic fluxes of the sun... which I believe Moira dMacTaggart opened him up to by "fixing" the genetic bottleneck he inherited... which caused him to go nutsy fagan every time he overused his power. she opened the floodgates of his power and he still hasn't really dealt with that yet...although creating a wormhole to rescue Wanda has got to give him an inkling of what is possible.
To get back to your question, I was not unpleased by the depiction of Magneto in that movie and I positively stood up and cheered at eh end when Mags appeared in his colors and said "I prefer...Magneto!"
... and, of course, it put to rest the pronunciation of his name... which has always been a big thing for a lot of fans out there...LOL