I subscribe to comments on a lot of blogs, including this one, and to replies, and I manage a couple of WordPress sites and do not find moderation onerous—did not even with busier sites. Sadly, my new sites are for small organizations that do not have a lot of commentary, but I agree that having comments is intrinsic to blogs and I would be disturbed by much change to the default system. (O.K., I tend to not like change and am an amateur at this stuff, so my vision might be limited, but I am comfortable with the comments system as it is now.)