I've got to say I agree with pg on this. It's more important that Arc turn out well in the long run than in the short run. Also, although Arc isn't moving very fast, I have to say that the more I actually program in it, the more I appreciate its design. I still find myself missing the lack of a proper library/module/namespace system, and of course given that some actual libraries would be useful, but that's about it for truly major issues.
That said, I do think pg could do with talking to the community a little more, and vice-versa.