My exact take on that 2015/16 season. Özil was a average and padded his assists stats with corners, set pieces, crossese etc. When you watch those assists you hardly see any defense splitting passes.I hold that same view. In that 2015/2016 season, he wasn't particularly playing well. 2/3 of his assists were set pieces or passes into non-threatening area that the attacker made good use of.
Let's not act like he was dominating games and taking games by the scruff of the neck.
Most of the games I watched in 2015/2016, he was basically average apart from the assists.
But the best Özil has played in my opinion was the 2017/18 period before he signed his current contract. That period between end of October to about start of December 2017. He turned into this dominant player i had hopped for when he joined Arsenal.
That months and a bit was the best version of Özil that I have ever seen at Arsenal. To me it was better than that overhyped first half of 2015/16 when he padded up 19 assists.
And remember during those amazing months in 2017 he did not get any assists if I can remember correctly. But everyone acknowledged how well he was playing.