While I agree that nationality shouldn't matter much, there are some indications (facts?) that in some cases it is important.
Imo, successful squads, much more often than not, have a solid base of domestic players in the starting XI (ideally 4-6) and it's not a coincidence because these guys seem to be important for the locker-room, for motivation, for acclimatization of foreigners or youngsters, or to simply talk to the fans. In Juventus, with the exception of Sarri's season when we won the league with only one Italian among the 11 who played the most, this was always a case.
Also, coincidence or not, some players from certain countries always seem to find it hard to do well in a specific country.