If I understand correctly, even in the private beta phase, the reputation threshold to edit other people's posts is 2000. While I've been doing my level best to try to get there :-) looking at the Users Page, it isn't obvious that anyone (perhaps other than Joseph) will get there much before the private beta stage is completed.
I think that the threshold ought to be a bit lower. There are a few posts that I've been itching to edit, and I think that the edits ought to be done before the public beta stage. As one example consider this answer. I'd really like to link the package name to the CTAN page, but can't. I'm also avoiding the temptation to request the edit in the comments, as I've already put some meta discussion in the comments, and more wouldn't look so good once we go public. Likewise, they are (as is inevitable) lots of silly typos across various pages.
I think it would be a good thing if we could establish best practices in our questions and answers early on. Allowing edits sooner would help that.
(Just so it is clear: I don't mean to pick on the user whose post I cited. There's other examples of a need for edits across the site and I am sure some of them are in my posts, too. It is only that I can edit my own, so if I became aware a need for editing, I've done it already.)