Seems to have an inflated sense of entitlement. Usually shows once a game or so in the form of a snotty, unnecessary, tactically stupid foul, often a booking. "you dribbled past me so I'm going to gouge you and then sulk" kind of thing.
A player with his CV could/should be the calm but tough minded leader in the middle of the park that, for instance, organizes the squad defensively on a hasty free kick in the last moments of a game that we had dominated for 90+ but were suddenly in danger of blowing. But like others of his vintage in the squad, talented players and internationals who were good enough to make Sky Six sides but not quite good enough to stick there, and ended up with us, he's not commanding anything.
A younger player can run hot and cold, right? For a player in his 30's... since the stamina and pace and the physical gifts are not quite what they once were you expect stability, consistency, nous, good judgment, guile, steel, maturity, leadership....
Schneiderlin's not that guy, I'm afraid. And we need that guy. But he's not it.
(Neither is Delph, who supposedly had all those senior-player qualities and who also mostly had a good game vs Newcastle but has turned out to be an even bigger knob than Schneiderlin, as impossible as that might seem).