This is just a matter of physics man... tiny tot throws a brick at some marauder, he is going to catch it out of the air, laugh, and then beat her to death with it. I don't care where or how someone was raised, under what conditions, a preteen just doesn't fit the role. Girl could've been raised by wolves. Doesn't matter. Like I said, even the old model was pushing it... I would buy that she can maybe fire a gun and is a little wise beyond her years, but taking a switchblade to the back of some horrid creature with real physicality is pretty hard to swallow for a 12 yr old.
Ellie is
14.
Now with regards to physics, I haven't seen her do things are beyond 14 year old at this point. Perhaps you have preconceived notions about what a 14 year old girl can or can't do but I have yet to see her do super human unrealistic things.
Lastly, catching thrown bricks is not easy no matter how strong you are if you are not prepared for it. We have yet to see that portion of gameplay/trailer where it happens. More importantly, adrenaline plays a key feature during the time of great distress which elicits the fight or flight response.
As far as i know, child soldiers are not simply tough kids with guns, that kind of stuff bends your psyche, especially if you're a child; moreover, i think they often use drugs to pump those kids into the battlefield, which alienates them even further.
I hope ND will handle it well, and not resort to too many one-liners and shit.
EDIT: I mean, i hope Ellie won't be a caricature like HitGirl or something like that.
You are right. However, the point remains that they are forced into this unforgivable misery from an age as young as 10. So in order cope they accept their rotten fate. It's similar with Ellie. She had been leading a sheltered life in quarantined zone for the first 14 years of her life. If you have seen the dev interviews by game informer, you'd know that the zone was place of strict regime and brutal tactics. Hence, she would have been exposed to the harshness of life from the very beginning of it.
If I have learned one thing it is this: Ever since the advent of internet, kids in general have been maturing faster. I am nearly quarter of a century old and I have seen kids less than 3/4 my age be able to grasp concepts that I would have thought were improbable. Whether through force or care the capacity of successive younger generations to adapt surprises me. So in turn what Ellie's character is being portrayed to do seems quite natural to me if quite a bit brave.