I submitted a political thriller, Eternal Night, to about fifty agents. All turned me down, two based on the full manuscript and the rest based on the query. I've begun reediting the novel, with the hope of sending it out again. Is there any use in sending it to the two agents who liked the idea enough to ask for the entire book but didn't like the writing? If there is, how should I phrase my new inquiry - "I have significantly rewritten the novel, and I believe now that it's considerably better than it was when I originally submitted it"?