Here's the thing: most law schools don't really care why you want to go to law school. They aren't particularly concerned with your "concerns". Most people didn't know what they wanted to do until they were in college and this is why you writing about how your conciousness was raised about issues of global justice will sound hollow and naive--because it's so unbelieveably typical, yet most people write about it as if they are the only "enlightened" one on X issue because of their "unique" (read: completely typical) college experiences.
I had this same problem when thinking about my PS. I identified myself as a feminist activist in college and wanted to write about why I wanted to fight for women's rights and how my unique experiences made me connect with the writings of this or that feminist theorist. Except anything I wrote sounded generic and "angry" and most importantly, wasn't about ME, but was about a very common intellectual stance on an issue that has been treaded on a million times over. I know when you believe something so strongly it is difficult to seperate that belief from your identity, but really, no one wants to hear about another college kid whose eyes were opened to the injustices in the world. As hard as it is to hear, that is not what makes you special to the admissions committee. Try to dig deeper, beyond your interaction with ideas, into who you are.
From another thread:
I JUST CALLED AND SPOKE TO ADMISSIONS COUNSELORS AT BOTH BERKELEY AND STANFORD. HERE IS WHAT THEY HAD TO SAY,
BERKELEY: "WE WILL BEGIN ACCEPTING THE HIGHER SCORE FOR THE 2007 ADMISSIONS CYCLE"
ME: "THANK YOU."
STANFORD: "OUR POLICY WILL BE CHANGED TO ADHERE TO THE NEW ABA POLICY."
ME: "DOES THAT MEAN THAT YOU WILL BEGIN ACCEPTING THE HIGHER SCORE, RATHER THAN AVERAGING?"
STANFORD: "IT MEANS OUR LSAT POLICIES WILL BE CHANGED TO REFLECT THE ABA'S DECISION."
Take what you want from that, but it sounds good to me.