I am not afraid to say this; probably because I've said it a hundred times over the past few years; David de Gea is massively overrated.
He's a superb shot-stopper, one of the best I've seen, make no mistake about it. But I think he brings a lot of pressure on himself. He has zero or little presence. I think a lot of the chances teams create against us, that De Gea saves with a great low dive from close-range, come about because he lacks this authority to own his penalty area. If De Gea had more authority, we couldn't conceded as many opportunities. I think a keeper like Loris (who has a mass of authority and absolutely owns his penalty area) or a Neuer (best in the world) wouldn't make as many brilliant saves if they were United's goalkeeper but they wouldn't have to. They do the simple things really well. De Gea can't do the simple things well. He is a six-yard box goalkeeper. The others are 18-yard box keepers. They sweep and clean. De Gea rarely cleans anything up. He is a shot-stopper of a goalkeeper. It makes him look an awful lot better than he actually is.
I liken his abilities to a great debate I used to have over who was better - Vidic or Ferdinand. For me, that was a no contenst, Ferdinand was five times the defender Vidic was. The reason Vidic got labelled a great defender was due to the fact that he used to pull out great tackles in desperate times. Like De Gea, his highlights reel looked great. But Ferdinand never made great, last-ditch tackles. WHy was that? Because he was way too good a defender to ever be desperate. He read the game immaculately and swept everything up before it even became a danger. Rio never had to make desperate tackles (he rarely made tackles he was that good - rarely got booked). He would see the danger before it happened. Neuer is a Ferdinand. De Gea is a Vidic. De Gea has to pull off great saves on a regular basis because he doesn't do enough to quell the danger.
It wouldn't bother me one iota if he left. I' like to see a goalkeeper brought in who can own his domain. De Gea's never been an authorative figure. And because he doesn't sweep a lot of danger away, he has to put up with so many shots at him. I know he saves a lot, but he brings it on himself.
I have no problem with your view until you bring the haphazard keeper Lloris into the argument (now there is an overrated goalkeeper who has more mistakes in him than a drunk dyslexic kid sitting an English exam)