Arnautovic is a decent lad but he's a typical player that excelles at a midlevel club where there's far less pressure. Don't forget he was once dubbed as a next big thing but flopped massively at Inter, went to Werder (top 3 club in Germany at the time) flopped there as well and had to go to ****ing Stoke to revive his career.
But he did revive it, that's something. You could be right though in that he thrives in the less pressure atmosphere of midtable clubs but would bottle it at a bigger club.