No MCs were fundamentally damaged in the way the defended. This was a known bug confirmed by SI, its been there for about 2 years.. You could make then defend, but they didnt defend anywhere as near we well as they should do. It's actually got nothing to do with pressing, but their positioning. In FM12, MCs dont position deep well enough and track as well as they should, its made much worse in 4-2-3-1.
I actually kept a lot of clean sheets, although its completely irrelevant. it doesn't change that there was a bug there.
like I say again it is your tactics, i use 4-2-3-1 in some saves and cover the most ground, they have excellent positioning especially when I am defending, they track every time I lose the ball so what you are saying applies to your tactic not mine.