Juanjo, I seem to understand that adding new nodes is a pain in the neck, as you have to rewrite them from scratch, BUT... One I could really, really use is the shadow catcher. Oh, and some kind of panels-like node would be nice as well - think IFW2 panels/tiles, or the one whose name I can't recall at the moment from Denis' collection.
On this particular subject, in fact, some kind of "regular variations" node would be great - think of a paneled wall where no two panels have quite the same colour, or glossiness or whatever - that's easily done within LW (again, thanks to 3rd parties) but not within Octane, and yet it's rather important for architectural visualization...
Cheers!
ADP.