The reviewers have been praising the AI for the way it functions.
Pardon me, but I choose to trust the 75 perfect score reviewers who all think the AI is tits, than the anonymous source watching his cousin play a suspiciously street-date broken game.

Misleading E3 demos that use scripting to fake features are par for the course this generation.

please check difficulty setting.

this

Easy = Declassified AI, Medium = Serious Sam suicide bomber AI, hard = E3 footage AI. Sounds perfectly reasonable scaling difficulty like this.

"The enemy NEVER tries to post up in a room and ambush you, they definitely NEVER run away and hide to preserve their own life, and they NEVER beg for their own life after being beaten to the ground and having a gun pointed in their face. So I have to ask, why was this issue completely overlooked by those who reviewed the game?"

Strange, Jim Sterling's review explicitly mentions otherwise:

http://www.destructoid.com/review-the-last-of-us-255287.phtml

It should also be noted that the artificial intelligence of the Infected is remarkable. While not exactly careful, Infected actually know enough to not charge at you in a straight line. During one moment, I was actually snuck up on by a monster, who turned and ran when I spotted him. He came back with a friend, and proceeded to dart from doorway to doorway, in an attempt to confuse me. Human enemies aren't quite that tricky, but they do try to outflank you and keep you moving. The Last of Us definitely boasts some of the best A.I. I've ever seen, and I'm very cynical when it comes to A.I. boasts.

i've always wondered what the real end game is for "amazing AI".   i mean there is a balance between smart AI and fun AI.

"The enemy NEVER tries to post up in a room and ambush you, they definitely NEVER run away and hide to preserve their own life, and they NEVER beg for their own life after being beaten to the ground and having a gun pointed in their face. So I have to ask, why was this issue completely overlooked by those who reviewed the game?"

if I was getting ambushed all the time would I really find that game fun?    ..i mean the game intends for me to progress so do I want a level design that encourages camping becauses pushing forward will get me anhilated? 

to me great AI simply means variety.  keep the game intersting by not always coming at me the exact same way.

obviously i haven't played TLoU but what i've seen looks very interesting.   seeing how differently an area can be played depending on my action is the definition of great AI imo.  If i want "intelligent" AI i'll play against another human,.. which btw I typically hate.   getting anhilated all the time sucks.

I didn't state it was true anywhere in my OP :P

I think TC can close this topic. It's been debunked.

Eh, I'll listen to the reviews and judge it for myself for next week. But I do believe the E3 demo was scripted.