wow weird, the same thing happened to me. I got a 710 on the verbal and a 5 on the AWA. I was expecting at least a 5.5. While a 5 is not appalling, it is something to worry about given I am applying to social sciences. I really thought I'd jump this GRE hoop successfully....and now this...grrrr!
I also wonder if ets is telling the markers to be more difficult with the assessment. The reason i say this is because I wrote the GRE last year but I retook it recently because I totally bombed the math last year. The point being, last year I got 5.5 on the AWA and i didn't even have time to finish! This year, I made sure time management was not a problem by practicing. I just don't get it. I know my writing was better this time around.
Anyway, what can you do? A re-score is out of question at this point. I just hope it wont be a huge deal.