(What has been suggested so far)
Idea 1.) Only ones that can use automatic weapons and have a slightly higher dart limit.
Idea 2.) Forced to always walk and can't "stealth".
Idea 3.) Must always have 5 weapons on them at all times.
Idea 1.) Their "stealth" can be just taking all of someone's tabs and have a five second head start after taking.
Idea 2.) Can "stealth" without a weapon.
Idea 1.) Gain a number of tabs every main session (# of tabs is unknown but but this writer suggest 7)
Idea 2.) Can not stealth kill
Idea 1.) "If they kill someone, the dead one is immediately tied up and walks to The Hunter. The dead one is still considered dying, and will die fully in five minutes (they can walk away and respawn). While in thous five minutes, the dead one can not run away and can only talk to the Trapper who killed him. "
Can tie a cloth (we can pick an arbitrary color later) around a piece of equipment to improve it. Shields gain the ability to resist mega darts and those chems that turbo-penetrate (can't remember which color right now... oops). Armor adds one HP to chest armor. Maximum of one improvement per person. Engineers can only upgrade one piece of equipment per session, and the upgrade lasts the whole session, regardless of whether the Engineer or improved player is slain.
As for cons: cannot use Chems. Zero. Find a medic.