Counterwise said:
Also the mute character does nothing for the game, he seems like an outlander in the game
Well...that's because he basically
is an outlander - at the end of the first game, G-man recruited Gordon to become a sort of interdimensional hitman, and . When you confront Breen at the end of the first game, Breen mentions G-man and how Gordon's "contract is open to the highest bidder."
While Gordon's silence is occasionally conspicuous, it would be a lot worse to have rolled out Nolan North and given him a bland personality to serve as the lowest common denominator-protagonist. His silence leaves his unspoken relationships and interactions with the other characters to the imagination, which is always going to be better than anything Valve writes for him.
Half Life 2 in a nutshell:
Hi, I'm g-man.
Cool.
Go there.
We're the symbol of a police-state and corrupt law-enforcement
Go there.
Go there.
Irrelevant exposition.
Teleport.
Go there.
Go there.
Hello, I'm the bad guy.
Go there.
Gravity gun!
Go there.
***** betrayed the faction who worked for the benefit of... something.
Go there.
Hello to my quarters, I'm evil you know. Did I tell you I'm the bad guy?
Super gravity gun.
Gaah! And I would have gotten away with it if it wasn't for you meddling scientists with their unconventional weapons.
Congratulations, you beat the game
But stripping a game's plot down to its components doesn't prove anything. Halo is "Evil aliens want a killer macguffin, so you have to blow it up." Mass Effect, a game renowned for its story, is "You've got to find out what Evil Space James Bond is up to, by shooting stuff. Turns out he wants to feed the galaxy to some robots. Stop him." Just because they can be ultrasimplified indicates nothing about narrative depth, characterization, immersion, or any other aspect of the story.
There's enough hints dropped throughout the game to make the backstory and plot clear, and the fact that you need to make the final connections yourself is part of why its so satisfying. I can only think of two reasons you could think the plot was thin in HL2: 1) you weren't paying attention, or 2) you have a very limited imagination.
You know what, forget it. Think of it this way: everything you love will be scorned in five years as derivative, overrated garbage, too.