Messi has his character
Ronaldo has his character
Ibra has his character
Pogba, Griezmann, almost every top athlete has character.
It is perfect scenario if the player can blend in, but it is also the club, the manager to well handle the player.
A "big" club like Arsenal, a big name manager like Wenger, should be able to take good care of player's character and attitude.
If we can't handle Sanchez just because of his character/attitude, we can forget to get any top player and his service for long.