However, this requires a very strong understanding of the team

which is almost impossible to achieve in a road game.
Choosing to attack separately is like waiting for the defender who is stuck in position. This is why ZERO HOUR is more suited to 5 players playing together and to be honest ZERO HOUR is not nearly as entertaining as R6. The reason why R6 doesn't continue to improve the realism of the game is because it is currently just the right amount of hardcore for R6.