Have you not noticed a correlation between Kompany's form and the way the team is set up?
Playing deep and having a tight midfield in front of him = world class
Playing an absurdly high line with a midfield that doesn't pressure the ball = reckless idiot
Kompany last season kept coming charging out trying to win the ball early, do you think he's just decided that? Of course not. He's being instructed to play higher and more aggressive. And when he sees that Fernandinho was the only midfielder putting any kind of pressure on the ball, he presses even higher, which inevitably leads to mistakes.
Very few defenders look good playing a high line. Remember Chelsea under AVB? High line, John Terry was an absolute embarrassment, people were calling for him to retire. Last season under Mourinho, he was playing deep, defending his 18 yard box and he was the best defender in the league.
Same reason Nastasic looked like the next Paulo Maldini in 2012/13 and the season after when we switched to a high line, he looked like the next Steve Redmond.
The only way you can play a high line is if you've got midfielders who have high energy who put pressure on the ball to win it back high up the pitch. That is the Barca model, and the one we are seemingly following. However playing a 442 with Yaya and Fernando, there is no pressing the ball whatsoever, so playing them two with a high line is just a disaster waiting to happen. West Ham away being a prime example.
If we switch to a 433 or 451 variation next season, which seems likely, the extra body in midfield will allow us to compete more in the middle and not get as overran as last season. I'm convinced you'll see a much improved defense and a much improved Vinny because of it.