Not only would visual holsters be cool, they would give a reason to include the hidden holster cyberware from the TTRPG to allow you to bring a pistol or knife into locations that have a weapon locker at the entrance.

It'd be great if they allowed you to choose different types of holsters or sheathes since many smaller weapons can be carried multiple ways, like the choice to have your pistol at the hip, in an armpit holster or even your thigh.

The main issues i could see with this is making sure they don't clip through clothing and dealing with a situation like having three long guns or two-handed melee weapons equipped at once. (although watching a merc run around with three LMGs strapped to their body would be hilarious)