FPL has no real strats, it is way more based in pure aiming, and Xantares has a lot of that. Against real teams that will flash you off positions or molotov you out and check all the positions it is harder to play purely on aim. Big never was a team which relied on aim so of course they performed poorly without their system.
They also didn't only point to communication issues, but rather with their whole team system. They didn't knew who would entry frag, they didn't know which positions each player should play. This plus the communication issues caused