there's a lot going on over on the csound list about OSC and csound. i think pd is the only thing that can recieve it now.
As far as I know, you can also use OSC in Supercollider.
My 2 cents on PD's gui: I agree that the present gui is minimalistic, but that should maybe be seen as a plus. I would give priority to pd evolving into a full-featured audio/graphics/video processing environment, rather that striving to look cool. Tcl/tl is very portable and feels responsive enough to me even on my old laptop (Pentium 133) which is not really the best system for realtime audio. I cannot say the same about wxWindows. On the other hand, I would welcome basic preference options for things like background and font colors. On OS X, I tend to work with pd with my display set to black and white and my gamma reversed (this basically gives me a white-on-black look and reduces the eye-strain due to the monitor's light beam). You can get access to that via the Universal Access preference pane or by using the shortcut CTRL-ALT-APPLE-8 and setting your display to 256 colors.
::: sam :::