Therein lies the conundrum. Club football means a full preseason, getting to know the coach's strategy and gelling with your team mates.
It also means that you know how other teams play and their players.
National teams don't have a preseason per se, NT coach may have a totally different philosophy and if you have a lot of overseas players then you don't know your teammates, let alone you opponents.
ManU is the closest club to the conundrum. As they have changed coaches each bringing in a few players to fit with that coaches' philosophy. Today they have a hodgepodge of players that just don't gel.
I am still giving Popa the benefit of the doubt as he has had no friendlies where he could have tried different players. BUT like any other coach, he has his own philosophy, and some players, no matter how good, just don't fit into that philosophy.