So, having never picked up a comic book in my life....I would say this was a very good movie. I've seen all the X-Men movies, Avengers and all the rest and I seriously think if you didn't like this movie you either don't like superhero movies, or you're too wedded to whatever is in the comic books and can't disconnect from them enough to enjoy the movie.
I sometimes feel this way about Tolkien movies, but I think the key is to just enjoy them for what they are, and not expect them to be a movie version of EXACTLY what you know from the comic books.
As for the plot points mentioned...
Spoiler!
It's hokey, but I think Magneto's control over the Sentinels went down into the circuit board level. IIRC, they did show the railroad tracks being split down into many very thin wires, and I'm assuming that went beyond "muscular control" if you will.
As to Mystique's adaptation ability morphing into the sentinels being able to replicate mutant powers (something Mystique cannot do), my assumption is that after years of research they took the basic adaptation ability that Mystique has and "improved" it to include not just replicating the look, but the actual power. If you assume that Mystique's adaptation is at the genetic level (which it obviously is), and that mutants powers are derived from genetic mutations (which it obviously is), then it's not TOO big of a stretch to combine them and then improve upon what Mystique can do. Heck, Rogue can already absorb powers, so we know that mutation exists. Perhaps it should've been Rogue, and not Mystique, they had to get DNA from...