I'm really happy with Lingard's development lately, he has really started to up his game in the CAM role and it makes our attacking play a lot more fluid.
It's a shame that at the age of 25, he still seems to have immaturity in his mentality, which might be stopping him to combine good performances with proper output in terms of goals and assists and that is what makes a true world class player.
However, he could prove prove to be an excellent squad player to provide the needed competition and different skill-set throughout the long seasons. As of right now, from the three number 10s we have in the squad (Lingard, Mata and Mkhitaryan), Mikhi is the one I would sell and it's very unfortunate, but he hasn't showed the passion or consistency to claim a spot in the squad, let alone in the starting 11.