Yeah, Willock would have stood out more to Wenger than Nelson - not because Willock was better but because everybody who's seen Nelson already knows that he's a potentially huge star in this Arsenal team, that's been apparent since he was 15.Got the feeling that Wenger really likes Willock . Nelson probably outshone him in pre season and Joe seemed a little out of his depths in latter pre season games but Wenger has persisted with playing him .
Saying that, Joe Willock's had his own hype about him, especially after his Victory Shield performances for England U16s. Some were already saying he's potentially the best Willock. He played as an AM/winger then and was always more of a passer than a dribbler like his brother but he's still handy on the dribble as we've seen.
I'm not surprised Wenger likes Willock as much as he does considering how his development has turned out so far and the kind of player he could shape up to be. He's had a major growth spurt and looks to have hit the 6 foot mark. It's not just the physical and technical aspect to Willock - he looks competitive, willing to put himself about. Doesn't shy away from 50/50s, uses his power quite well for a player with little experience. Add to that his growing physique, his "eat-up-the-ground" dribbles, good passing ability......once he gets comfy shooting and getting into final 3rd situations for the 1st team/U23s, he'll basically give Wenger an opportunity to start his Diaby project again. This is the perfect kind of midfielder for Wenger. The way he develops, he could end up being an excellent all-rounder. Not quite Vieira (who was a freak) but in the same mold.
Very real possibility that one day we see a Willock-AMN midfield at least once. They're both all-round CMs who can win possession and do damage with it.