Players that get to the top of the ranking are those who have the least amount of flaws in their games. They have mental, technical, physical and tactical qualities with a unique ability to overcome all kinds of adversities, in and out of court. They do not oscillate the quality of their game for too long. They have to play well all year round. A good example of what a limitation can do to the game is what happens with the great Spanish player Albert Ramos Viñolas. He is very solid playing behind the lines, and he is very focused. It is very unusual to see him make mistakes on two consecutive points. After any kind of mistake, he just gets back to the game with no sign of regret.
He has been making excellent matches against top ten players, and he is getting nice results, even winning tournaments.
So, what is the problem of his game? It may sound pretentious to point a flaw on a player that is ranked among the 20 best of the world. But, will do anyway. Being a solid ground player, with a good serve response, he is wasting too much energy to confirm his services. And why is that? He is 1,88 mt (6´2" feet) tall, strong enough to have a good service. Except that he does not. As seen in pictures and videos, he seems to have a flexibility or mobility problem on his serving shoulder. To compensate that he bents his body too much to the side, producing a rather week strength vector in contact with the ball. His service does not hurt anybody on the circuit. He always has a hard time to confirm his service, wasting a lot of precious energy for somebody who has to play well for months. If he could just save the energy scoring some points with a good service, he certainly would perform better for longer. Instead of playing long points, 8 to 12 balls, he could just lower the average on his serve to 3 or 4 balls. It would make a big difference.
The proper technique can only be achieved if he works on his shoulder´s mobility, making it possible to balance his body and produce more power and more accuracy on his serve. With a new service, together with his solid groundstrokes, he would certainly reach a higher rank.