It does hurt us as we are giving the ball away and coming under pressure from it. If he was a top class shot stopper and could deal with crosses it could be over looked, but he's not (besides for short range reaction saves as you said).I’m not so concerned with him kicking it out of play, we’re not directly hurt from that.
Bigger issue is how poor he is with shots from distance and it’s because of his footwork. Iwobi’s goal is a perfect example.
He dives with both feet on the ground from a static position. You get very little launch that way. He has a good view of the shot, a couple of quick steps his right would give him momentum and a better launch for an easy save.
I’m surprised there’s been no improvement in this area, it’s why he’s often beaten from distance so easily. This doesn’t take away from his short distance saves, which is fantastic