I disagree that Clark is any more a passive character than he has ever really been in the past. Even him hiding himself from the world was an active choice he made, and he continued to do good while doing so. Superman has always been about reacting to things to a certain extent, its inherent to the character and really to the idea of a superhero in general, but Clark's actions still drive the story forward in MAN OF STEEL in several respects until the Kryptonians arrive, at which point, of course he's going to be a reactive character. He's still a fairly proactive one though."
I view the end of MOS as neither a good or bad choice, simply a nontraditional one. The film did resolve the film's central conflict, which was Clark starting to resolve his issues about his heritage and finding his place in the world. The event in Metropolis, as big as it was, was secondary to the overarching theme of Clark's personal journey.
Since the next film seems to be spending a large part of the film addressing the "unanswered questions" from MAN OF STEEL, I don't have much of an issue with the way MOS ended. Instead of tying things up neatly, it left us with a lot of questions, concerns, possibilities, etc, and I like movies that do that.