I don't think that would work:
1) Driving with a wanted passenger will result in committing an infinite-neverending crime. You would become most wanted in 5 minutes. Evading will be impossible since you basically always committing a crime, and even if you are at the corner of the map, the wanted level would still be increasing. Moreover as threat? Total Nonsense. Just like being a threat after robbing a store with a fire exstinguisher.
2) You can always pop the tires or destroy the car or create a roadblock. It's the teamwork that's missing. Cops just go after 1 criminal like soccer players run behind the ball. 1 Car should chase, another car should block and intercept, and another unit should create a radblock with snipers and M4 shooters. Tires popped, car blocked if not destroyed. Suspect on foot, arrested or killed. Killed more often.
3) The driver should'nt be able to get a wanted level, but just to be asked to stop, and then get a wanted level. Or maybe the driver should be able to take damage even if innocent if transporting a wanted suspect. That's it, even if it's too much for me. But i don't think getting a wanted level just because you are transporting someone that is wanted is fair, and even a threat crime, so they can kill you for that. Cops are already too op. This shit won't improve things.
Btw Irl the Penal Responsability is Personal, so only you will have to deal with the consequences of your crimes. If a driver is transporting a criminal, he mustn't become a criminal too.