I'm not sure it would be nice. All sorts of things are unrealistic in GTA. You can speed, run red lights, smash into cars and buildings, run over pedestrians (if there's not a cop right there, without becoming the target of a police manhunt. You can shoot someone dead, in full view of a policeman, and if you can hide in an alleyway for a few minutes, they'll forget you ever existed.
All of this is in the service of creating a fun game.
A mode of operation in which you can "come quietly" doesn't add to the fun.
(Although in earlier GTAs there was the "Busted" option, where a cop touches you. Instead of respawning at a hospital, poorer, you respawn outside a police station, poorer.)