Remember 2 seasons ago when Jesus just joined, Martinelli was cutting in for fun and crossing with his stronger foot for him to head in? We have seen so little of that these 2 seasons. I really don't think it's by design, but I am also a little disappointed with the progress he is making as a winger given that it was highly publicised Arteta finetuned Sterling's game and made him a far better winger etc.
I don't think it's just a confidence issue either, he hasn't really grown as a player for the past 2-3 seasons with or without goals. His overall performance as a player is highly lacking and all of us kept saying he will come good, but his trajectory is downwards. All the points above are valid imo.
Just remember last week, there was a moment he made a good run, we found him in open space, he dribbled into the box with 2 players free in the middle, but he decided to shoot into the side netting. It reminds me of Nketiah, too eager to impress.