Bruno is an end product player. If that dries up, even for a couple of months, the knives will be out for him as his bottom level is very low. He'll always be on the edge.
And when you analyze the end product part, alot of his goals are penalties ( 4/8) although an aspect of the game we were inconsistent with.
If you analyze the assists you'll see that a significant portion are simple passess to the attackers who through there share brilliance converted it. But this should not be underestimated because those assess are made quickly and timely.
His impact is a combination of timing, new signing effect and replacing very very shitty players with a competent and hardworking player. The level is definitely going to go up.
People really under estimate how bad Andreas, Lingard and Mata are. They are pretty shit honestly. One has a tunnel vision and lacks football intelligence, the other has no footballing ability and the last has just aged too early and is weak, perhaps the weakest player in the epl.
Pogba and Matic where absent for very significant part of the season, so we where bound to see improvement when they returned.
Martial and Rashford have finally started in same team in the longest stretch of matches since the season started and Greenwood is starting more games and has improved physically.
So we where bound to see major improvement in both results and play and no one can predict how much improvement we could see in having a player of Grealish's ability in the team.
I firmly believe if the transfer comes through, he will surprise alot of people.