I think it's better to give ungistered users post permissions.
I personally have too many online accounts and I want keep them as fewer as possible. I come here at least several times per week, I would like to register an account. But if I just want to post one suggestion to weinbar, I just don't want to get another account, although it really doesn't hurt.
One suggestion to your CP. The original CP looks bulky. and the top "frame" occupies a lot of space. If you can customize it and make it look cleanner, it might be better.
Just my $.03.
By the way, I have one account with you and I like it.