You are sure just means you don’t know. You can’t assume something with confidence. Pogba does a job for us there without no fuss. Grealish does not have the personality to do a job he is very much a maverick and requires that role within a team.
4-3-3 works if Jack has the license to do what he wants. That job is for Bruno. It doesn’t not work. We would need to be a Saul Niguez to improve our current midfield make up. Not Grealish as I think he would cause a bigger problem that what Pogba causes.
I find it funny people say the balance is messed up but want to replace Pogba with Grealish. Makes me think people deep down are scared about the quality we will be losing.