You know what the problem with casting an unknown is? THEY'RE UNKNOWN.
You can't argue the positives and negatives of an actor if you don't know them.
You just don't know any kids that could fill the part. How about an actual opinion to back up your negativity?
Just because you are enamored of the current Hollywood system which in my view is little more than an Russian imperialist view of creative inbreeding (which may be colored by a degree of anger in that they want to remake something that is perfectly on it's own, or may not be), doesn't mean what I just stated isn't an opinion. Also, how do you know that I don't know of anybody who could fill that part? You've never looked inside my head, just as I have never looked inside of yours.
All I am saying is I'd love it if for once, instead of just picking a similar wee relative of another bankable star, they actually put a little thought into the search. There are literally thousands of kids out their with talent, who will never have a chance at a acting career simply because no one is willing to go out on a limb. Hollywood is stale, and watered down, and because of that, their entire industry is in jeopardy. The very point of screen tests is to see if that unknown person might fit the role, I'm not asking that casting directors put someone in a role by lottery, I'm just asking that they look in places that go beyond the cute little relative of someone who already has a career.
Certainly, it's possible that the famous kid sisters may be best for the role but that sort of casting pick is so common now a days that I would love it if they searched beyond the usual suspects.