The gameplan for Netherlands was to have Nigel de Jong and Jordy Clasie man-mark Lionel Messi of Argentina in the World Cup semifinal. It was effective for them, but Germany play a different style. They like to hold possession, but will also look to break. The break off the counter often starts with one of their deep-lying midfielders. Germany have been successful with this system and do not need to change. They need to score first and that will come from not changing their system.
Part of the reason Germany can feel comfortable sticking with the system is that the defense has solidified in the knockout rounds. When healthy, Mats Hummels has been the best defender in the World Cup. They did concede a goal late against Brazil and were highly upset that they had conceded it. Hummels and the sweeper keeper Manuel Neuer give Germany plenty of faith in the defense, which allows them to keep tactics the same in front of them. According to FiveThirtyEight, Germany has allowed 0.49 fewer goals per game than the average World Cup team.
Defense was the weak spot moving into the tournament, but the offense was never questioned. They have averaged nearly two-fifths more goals per game than any other nation in the world. The attack through the middle of the pitch could make Messi defend more, thus expending more energy. If Germany can maintain possession and Messi is once again lax on defense, then acres of space could open up. This will put more pressure on the very good Argentina defense.
Of course, Germany has its fair share of attacking prowess. Thomas Müller is one goal away from two-straight Golden Boot crowns. They scored seven against Brazil and four against Portugal. Even in the match against Algeria where they struggled to find the winner, they created more quality chances than any other team in the World Cup. Man-marking Messi will ratchet down the attack. Germany needs to put pressure on Argentina.
Germany need to play their style and that means letting the normal defensive stature contain Messi. It could haunt the Germans, but it will allow them to play what is familiar.