Not all children actors are terrible. I thought for a few scenes, Carrie Henn played her part fairly well. Then again, she wasn't an actress when they picked her.
Alien was a horrible film without children. But Halloween had children in it, and that movie was fine. Just as long as it doesn't turn into E.T., I'm on the fence. T2's Eddie Furlong is admittedly sort of annoying but strangely quote-worthy all the same. I make fun of the guy with my brothers a lot, but who, at that age, wouldn't have wanted a terminator?