Watching the review now, but I agree with the numeric rating for the singleplayer. Marine AI is too poor - However, the Alien AI is pretty great, they just needed to be faster moving. The story is too weak, but what can you expect from an AVP game? Plus the voice acting is "meh", a couple of the boss fights aren't great. So in that regard it's a fairly average single player experience, but bumps up to a 7 because of the visuals (it really does look great in DX11) and the sound. Once the dedicated servers are live I foresee the multiplayer being more of a 8-9 range, maybe a 10 if they add a few things and polish it up a little.
As for iron sights, I really am a tad confused as to why everyone keeps screaming for them. The only possible explanation is wanting the magnification (like 1.5X zoom with most games), as you already have ADS accuracy when "firing from the hip" (if you pay attention, the Marines always have the weapon shouldered, minus the smartgun) in this game. Even on full auto the pulse rifle is nearly pinpoint accurate.