I'm not really feeling the current defence value, we currently have one of the most chaotic defences in the top European leagues and this is only exacerbated when we have Maitland-Niles filling in at right back. In all honesty I'm not certain of how to gauge defence if someone like Granit Xhaka sits in the mid 60s, but I know that Maitland-Niles appears very shaky when it comes to defending, really all he's got going for him in such scenarios is his physical prowess. He's decently quick but he's very stand offish as a defender and often suffers lapses in concentration. In my mind he's not higher than low 60s at most, though I'd consider going even lower.
Response looks high at first glance. Agility too, he's decent in terms of his range of movement but 83 is a very good value, no? In my mind a player with this high an agility value - to the point where it's one of the more prominent aspects of his game - would make use of such agility more than Maitland-Niles does. He doesn't come across as a player whose agility is a key aspect of his game. I personally wouldn't go over high greens.
A number of users have noted his composure on the ball, but for me that isn't enough to warrant an 82 in dribble accuracy. His footwork is decent to good, no where near the realm of yellows, which in the case of this particular set would denote a player who's very good with the ball at his feet. Maitland-Niles is casual in possession bordering on careless, and I feel that this may affect peoples perceptions of him as a player. He may come across as assured, but Arsenal fans know that his execution doesn't necessarily always match his perceived confidence on the ball. High greens at the most in my opinion, if that. He might even be more of a dribble speed > accuracy player, but this may also have to do with the fact that he's been marooned at fullback where he's more able to exploit open spaces with his speed.
I would have him on whites for all passing stats, he's the definition of a lackadaisical passer and it is not uncommon to see his passes wanting in terms of weight and accuracy.
Aggression could come up, he's quite an advanced player regardless of whether he plays at fullback or in midfield. Should be low yellows minimum.
I feel like teamwork and mentality are both overblown, I would say these are two areas where his game is quite lacking. Especially from a defensive standpoint, he is not someone I would consider a competent defender.