I also thought that entire telekinetic plotline to be unnecessary and it took away from the premise of the film. They could've shown more of how evil that kid will grow up to become.
You know, I forgot about the telekinetic stuff from the beginning, so that when Emily Blunt ran into her safe when the kid began having his freak out I was all "what the hell?" Then later on, when we find out she's telekinetic I was all, "oh right, there are telekinetic characters in this movie. The kid must have some sort of uber telekinetic abilities."
The telekinetic stuff was far too subtle. So much so that I forgot about it when it became relevant to the plot and it ended up seeming like something out of left field when it is in fact a logical plot development.