I'm sure it'll make it's way into UDK at some point, but I wouldn't hold your breath for these features just yet.
Unfortunately, with the advent of Unity and UDK, and self-publishing, no-one really makes mods any more. They just go straight into deluding themselves that they're an AAA-title...
Black Mesa has become the new Nuclear Dawn. That is, it's serving almost exclusively as a portfolio piece for artists. All respect where it's due - they're obviously making some good stuff, I just don't think it's going to meet expectations.