He gets forward plenty of times, often overlaps the wide attacker and is actually quite good technically. It's just that after such a long time out with some games here and there, he is starting to adjust to regular playtime without getting tired at the end. Also, some improvement in the final third is required, both crossing and shot wise( has a powerful long shot in him, needs to aim better).
Comparisons with Marcelo and Young is unfair considering both of them are basically wingers( yes, Marcelo too), and are poor defensively than Shaw, also being at least 7 and 10 years older than him.