I don't understand the argument behind the "He's a scientist,so he doesn't know how to aim down the sights..."
Really? Just because he's not a professional in the gun business he can't understand that to aim the gun he has to look through the sights? I fired a a air rifle when I was 9 years old,and my first reflex was to look down the sights when it was time to fire.I'm sure a brilliant scientist that's 3 times older than I was,and has some good experience in the asskicking departement would understand how to do it too.
As for the other argument about not needing to aim in HL1 and HL2,it's because the shooting was balanced towards not having to aim with iron sights ever.
I don't understand why it would be so bad.I don't understand why this small,even insignificant step towards "realism" is greeted with hatred.Having an extra option isn't going to turn HL into another brown and grey looking CoD.
You're not being a brave defender of the true gaming world,you're acting smug and condescending towards other games you appear to hate.