The reason why Trubisky won't put up big numbers this season: He doesn't have to.
Our defense is really good, and that's the reason why Trubisky won't have to put up big numbers to win games. If our running game improves as well, even more so.
Not to take anything away from Mahomes, but one of the reasons why he put up big numbers is because he had to. The defense in KC was bad, and they had to score alot of points to win. If you take a look at QBs purely from stats, you'll see many top performers come from either losing teams or teams with bad defenses. Garbage time, playing against a prevent defense, and calling more passing plays due to game flow, all pad stats.
If you have a strong lead, and your defense is playing well, then all the offense has to do is kill time and give the defense a rest from there. No need for long bombs, high risk passes, or no huddle offenses. I would be concerned if we're making 40+ passing attempts a game consistently, because it's usually an indicator that were playing from behind. A dominant win is where you get your 3-4 TDs, punish the opponent to the point they become one dimensional, and then tee off on the QB if they try for a big play. Maybe give them a little underneath stuff to kill time and give false hope, and then run the ball down their throats until you take 3 victory formation plays.
If Mitch can eliminate his mistakes like poor reads and over throwing receivers, while continuing what he does well, we'll be just fine. If the running game improves, even better. Mitch doesn't need to lead the league in passing or TDs. It probably won't happen anyway because our defense is so good and may even be better this coming season.