Puppeteer Putin said:
I love a cyclical discussion as much as the next guy, so I'll hop on.
I enjoy thr voiceless protagonist. It allows you to THINK through the dialogue that's spouted at you. Your free to think "He's a dick" or "What an awesome baddy" without being interrupted by some idiotic, goody-toe-shoes smart-cracking "hero" who, by the sounds of things, has only every read Hardy boys and Bond novels. You can fill the gap, if your immersed. Of course they want to get some sort of universal response, or some base understandng, but each playsers interpretation is their own - regardless if they think the same as what the character is being FORCED to feel.
Plus Gordon suffers from a severe case of autism. Yeah, how do you feel now?
How can it be unique? Each player has to do exactly the same as every other player. And, surely it's utterly immersion breaking if everyone is like "Yay Gordon's here, now go kill Mr X", when infact you want to join him, yet the game will only progress once you have killed him. It's only as unique as playing through Devil May Cry and thinking "damn he's awesome", or "damn, he's a dick" as the game is identical everytime for every person.
Plus, you show how it's lazy on their behalf not making a good character who is agreeable, without using shitty one liners or poor voice acting.
As for him being autistic, with his shot, maybe there should be more autisic people put into the military (but knowing autistic people, I think your comment was somewhat in bad taste. If true, bad taste on Valves behalf).