Responses to other blogs:
Beginning Republic: From what I've read of the Republic so far, it seems to me that the length of the Republic may be due to Plato wanting to be able to compare different ages and temperaments in arguments.

Homer and Mimetic Value Systems: In response to your last question, I think that common texts can be dangerous, especially when evaluation of one's mental attributes is based of memorization and "correct" knowledge of that text. This might be a bad analogy, but this question made me think of how Chinese civil service examinations under the Qing dynasty became basically useless because of the strict focus on Confucian texts.