The thing is De Gea played with Vidic and Ferdinand and none of them complained about DDG not coming out out of his line. Why? because they're top defenders and they know when and when not to pass around at the back.
Also, if there's mistrust between them then the person who should be organizing it is Maguire. He's the captain, he's the most important out of all defenders. De Gea needs to command his area during freekicks and corners, but really he shouldn't have to do that in general plays when we have the ball. At that time it's the defender's. The main problem is we have defenders that are neither calm nor composed actively trying to play the ball around at the back (which can also be attributed to the system, maybe they are instructed specifically to do it?) and when they realize they've made a mistake, such as opponents pressing them and they have no space to run to, they just give it to DDG. So of course I can understand DDG's frustration. After all, if the opponent manages to snatch the ball it'll be him that gets shit on when the opponent scores the goal even though it's most likely a collective, systematical mistake. Imagine the players in front of you constantly scrambling and you never know what they're gonna do, what do you do? you come out, it can lead into a mistake, you don't come out and it can lead into a mistake too. I don't agree that he's a big problem. We have bigger problems. Replace him with someone like Ederson and the defenders + midfielders will still find a way to make stupid mistakes that put the GK in a disadvantageous position. Hell, I can imagine Ederson coming out of his line only for Maguire or Fred to score an own goal. We just don't have an organization nor calmness at the back - the reasons why we brought in Maguire and so far it's been a failure. Meanwhile if we had a decent back four that don't try to outsmart themselves with playing from the back, with DDG still in goal, the difference is gonna be night and day.