For a winger who has recorded 23 appearances with just a goal and three assists are you sure this is the player Manchester United which is currently struggling needs? With the current situation I think united should be looking at very good players who can immediately make good impact as they join and for a fee not too expensive to give room to sign more. They need wingers who can guarantee atleast between 10 to 15 goals in 23 appearances.
Wonderkid transfers like Geovany Quenda are made with the future in mind. It's not reasonable to expect him to average 1 goal/assist per game already. Such players come along once in a decade and big clubs pay astronomical prices for them. Quenda will be a good player maybe after 2-3 seasons of regular playing in quality leagues and developing. They are not signing him as a savior. If they were looking for a player with high attacking qualities who could save United today, they would have to spend a minimum of 100 million Euro. Success doesn't come only by signing such players, you need to build a team and play players who are compatible with each other with the right tactics. For United, almost none of this applies. That's why it's very difficult for them to succeed.