We're still in the process on upgrading our networking to dedicated (from peer-to-peer). Ultimately it will allow us to make more quality updates, like weapons. We have a pretty good idea about what we want to add for that - basically some default weapons you can place in worlds to do things with (think a sword, rocket launcher, gun, etc). As far as custom weapons, that's still to be discussed. But the basics of the feature we have planned after the dedicated server update.
And to expand on that, I am really excited for it. I agree with you that I think it will make games more fun. Only hurdle is the reliability. Imagine being in a FPS game and the host disconnects, causing the entire game to reset. It'll just ruin the experience, so that is why it is planned for afterwards.