I, too, am new to this community. I'm working on development of a gnome-applet client using perl, and some toys. I've discovered that there are some things I want to do that currently can't be done with the client-server protocol.
Specifically, I'd like to be able to get the friends list of people other then myself, and get the comments count (and, ideally, the comments) for a given journal entry. Both of those seem to be impossible, but neither should be difficult to change. I'm not sure (haven't perused the code) but I'm not sure if it's possible to get the IDs of the last N posts on a given journal, and retrieve them.
Basically, my theory is that anything it's possible to do with the web "client" should be possible to do with a real client.