He's a very talented player. He is also young and inexperienced. He is far from poor.
Not sure if this has been posted before but it makes for good reading and suggests defensive mid is not his strength (which I think was already pretty obvious)...http://outsideoftheboot.com/2017/09/17/scout-report-douglas-luiz/
He's definitely got the ability, he just hasn't been used in a way that brings the best out of him. A constantly changing midfield three doesn't help either.
Great celebration. That passion is sorely needed. As noted above I think there is a real player in there, he's still learning his position and probably isn't being helped by Smith's strange rotation of midfielders. Certainly shouldn't be benched for Drinkwater's benefit; needs to start v Bournemouth.