That's usually my general answer for summer action flicks as a whole. I don't normally get into details unless asked, but I'll go ahead and talk more about my view of the movie.
Christian Bale plays John Connor very differently than Connor's other actors did mostly because the writers were going for a much different John Connor. In T4 he's a jaded war veteran who has nearly lost hope in the future he has come to expect, as opposed to the more hopeful version of his childhood and adolescent portrayals, and Bale does a good job at this role as far as I'm concerned.
Also, nothing in this movie really serves to "humanize" the machines. Marcus Wright is basically the 6 million dollar man and by no means a machine, as referenced in John Connor's wife's little monologue at the end of the movie.