No, we certainly don’t think things are perfect. However, some decisions were made long ago for what were then considered good and sufficient reasons. In some cases, a rethink is certainly valuable – we’ve changed policies on a number of issues. (Quick example: we now have suspensions, not just bannings.)
So, sure, we’re always willing to consider. In some cases, however, we will come out confirming our original policy: the reasons haven’t changed all that much.
As I said before, I think that not allowing editing means that folks are focused on content, not on grammar/spelling. If you weren’t there, you can’t imagine how awful it was back in the days when people jumped all over typos. Someone would post, “I’m upset, my dog died and my boyfriend left me and my house burned down” and the first six responses would be about spelling errors in the OP.