I have to be honest, I didn't see that and I watched the entire half he played when he arrived. I thought he played quite well for someone just off the plane trying to pass to people he had never met before. I didn't watch any of the Newcastle game. Still the Boss seems to like him and for a nominal fee, I don't think he was a bad punt. To me he looked dangerous every time he got the ball. I loved his acceleration and urgency when he received the ball, a bit Rosicky like.
If I had to guess, I would say Wenger liked the fact that he was pretty quick and had very good technique, was very strong on the ball (as you say) and really went for his passes. That giving the ball away thing isn't always a bad thing in a young player, we don't want players who just want to play sideways, and take the safe option. Obviously the club saw something they thought they could work with, so I'll give them a go at it.