I want to recommend to you an excellent book review by Cass R. Sunstein, at http://www.powells.com/tnr/review/2006_10_26 . The book is Our Undemocratic Constitution: Where the Constitution Goes Wrong (and How We the People Can Correct It), by Sanford Levinson. The first half of the review presents the arguments Levinson makes in the book for calling a constitutional convention and changing the U.S. Constitution substantially; the second half considers those arguments, discusses them, and for the most part rejects them. Here's a sample paragraph:
"It is true that the Senate and the electoral college, as presently constituted, are not easily defended as ways of promoting deliberation or protecting liberty. But the argument for a new convention cannot be clinched by reference to those admittedly serious imperfections. Sanford Levinson has valuably shown that parts of America's founding document are seriously flawed, and he has demonstrated that both representatives and citizens should treat the document not with 'sanctimonious reverence' but as the revisable product of fallible human beings. But nobody should be packing their bags for Philadelphia."