According to the interview I read in L'Equipe (today's edition) with his coach, he does encourage him to play a more attacking game but Monfils is the one who needs to believe in it and execute it.
Thierry Champion says that Monfils often gets that criticism but he adds that on critical moments, he does take the initiative and play aggressive. "That's the reflex of somebody who can read the game well".
Apparently, recently they worked on his game style.
Gaël said that he wants to play like Blake, within the court and hardhitting.
His coach doesn't think that it's a bad idea as such but he can't play just like Blake by always moving forward and hitting hard. He needs to move back a bit and then move forward with the ball.
Champion says that people need to give Monfils time.)
(at one point, the interviewer says to Thierry Monfils: "La stratégie n'a jamais été la tasse de thé de Monfils"
--->loose translation: Strategie has never been his cup of tea.)