This is a key point...
Yes, it will be tricky to get players not that used to each other gelling as a team in a different tactic. The sign of a great international manager is one that can overcome this and get a team to buy into his system and with his team-mates quickly.
Many other international sides mix a more diverse selection of players, those who play in different nations to each other, from different backgrounds and philosophies and achieve a blend far more successfully then the usual suspects from the Premier League European qualifiers.
Our insistence on picking from this group is lazy and a sign of the technical shortcomings of our coaches, not just the players.