Snip
Sometimes football players grow up to love a particular team and often find it hard to exit such teams and this could be situation David de Gea could have found himself in when leaving Manchester United. Right now there rumours and speculations that he could be on the verge of returning to the club he left some years back but I don't think this would be a good decision for the Spanish goalkeeper because Manchester United isn't in good shape at the moment and his presence wouldn't do much to change the status quo, so it would be best for him to consider playing elsewhere.
I don't like it when people use the condition of a club to judge which player should come to the club or not. Do you mean that United will never be back to their best form or they will be in this state forever. C'mon, it's new players that will come and change the performance of the club by improving it to a better one in order for the club to start winning trophies. United is a good choice for De Gea.
If you don't like it that's your choice but it's just what it is in modern football. Good players want to be in a club that are in their all time best and not in a struggling club because it's going to deny or reduce their chances of winning some trophies or even individual awards in their career. Conversely, which club would want to sign a player that is in a bad form? So it's same for the club, their present situation determines a lot in influencing players to the club.