I just feel people like him because he appears in a great game. Gordon is just lifeless. And I know you're supposed to be Gordon but then why give him a face and a name in the first place if Valve so insists on the player being the hero? Why not just leave it to people's imagination?
I think it's interesting how Valve did the opposite of what everyone else do and made the player an ugly nerd type of hero. Even the name Gordon Freeman sounds pretty out of place for a FPS. And he seems to get a lot of praise from Alyx, Barney, Eli etc because he can pull some plugs.