I agree. We're paranoid about scaling right now (loading the frontpage is a massive task, even with memcache), so that's why it's login-only for right now.
Generally speaking, it's better for new web apps to be paranoid that no one will care about your app, vs paranoid too many will be.
I agree, you can use OpenID, it's a lot faster to register.
Yes, for the .1% of people online that use OpenID. OpenID is a failure.