Another nice feature would be if I could subscribe to a blog and be notified once a new post is published.

Depending on the e-mail template it would sent out an e-mail with only a link or the excerpt or the complete post.

If you opt to build in this feature, you should also have an sender overwrite per blog:
On a web site you might have several bloggers and they probably would like to receive feedback separately. At the moment only one e-mail address for all blogs can be set.

Thanks
ralph