Honestly? I'd like to see Half-Life 2: Blue Shift. Get an idea what Barney's been up to this whole time - maybe get a chance at some different playstyles. I doubt Barney's personality is really conducive to "stealth" gameplay or anything like that, but his undercover position as a Metrocop opens up a number of exciting possibilities.
That sounds a lot like
Contract JACK for the NOLF series. Take away all the stealth and non-combat stuff, and that's the game you get. But wait, didn't most people hate Contract JACK and Blue Shift?
If they do a Blue Shift 2, they should make it a little more interesting. People already criticized Episode 1, saying it didn't bring anything new. What do you think they would say about Blue Shift 2?