In 4-3-3 Mata doesn't have as much freedom, he'd need to be more defensive and more one sided. I believe AVB and Robbie never played Mata in a 4-3-3 midfield three, but rather as a false winger. And when they did play him centrally, the middle park was always clearly in a 2-1 shape, leaving Mata more advanced in the free trequartista role, which he couldn't be in in a 4-3-3. What you described, I believe, is still the 4-2-3-1 formation, and you placed Ramires in the double pivot role. Okay, but I maintain that ideally there should be a deep passer, a la Lampard under Robbie. Rami can play there but it doesn't benefit his or the team's performances much, our possession and penetration would suffer. He's a rather one dimensional player, very direct, not as universal as Essien was.