The combination of Fassbender, James McAvoy (as Professor Charles Xavier) and Benjamin Walker (as Dr. Hank McCoy) definitely gives this misguided idea a lot of class, and speaks to how good the script must actually be. Fassbender told us during the Jonah Hex junket at ComicCon last year that he doesn't actually read comic books, and seemed perplexed as to how he ends up in so many adaptations. He just likes the scripts. (Again, further proof Jonah Hex had a fun one at some point during its troubled production. Fassbender was pretty enthusiastic about his role -- and he was one of the highlights of the film for sure.)
It must help that Magneto is a meaty character any way you write him. A survivor of concentration camps, Lensherr has always seen the persecution of mutants as another Holocaust waiting to happen. You sympathize with him. Occasionally, the X-Men have found his initial "They're out to get us!" theory is the right one. The sad thing is that his mutant loyalty turns him into the fascist figure he claims to despise. Should Vaughn take this into darker territory (and I'm concerned Fox won't let him), Fassbender and McAvoy's performances could be ones we all point to as proof comic books are rich with character material. Or it could be another "Well ... Fassbender was good." Let's hope it's the former.