This might sound harsh, but I think Maddison is overrated, and I'm not surprised he didn't make the England team.
There is no doubt he has some moments of brilliance, whether it be a great free-kick, long-range shot, or through ball.
However, those moments are inconsistent. Maddison is weak physically, easily thrown off the ball, and at times can feel like a passenger. He doesn't pull his weight, basically.
Also, he seems a bit too interested in the limelight, a bit of a "fancy Dan".
I don't think Maddison is what Arsenal need, since he's a showboating flashy player that lacks grit, but if they offer him £200k a week, his ego will probably take it. £60million for him, I think is good business.