First off, thank you all for all the information. This is super helpful!
This has been a big issue for me as well. I love what people can do in PAC, but I hate what people can do in PAC as well. In our last iteration at the end we implemented a system of actual armor you had to have in your inventory. If you didn't have the specific type of armor in your inventory and you had something PAC'ed on that looked like it, you're just wearing a cosplay suit basically. PAC is stupid hard to police so I think using something like this is the best method still of weeding people out, if you don't have a bullet proof plate in your inventory, you're wearing plate carrier with maybe a text book stuffed into it or nothing at all because in the end a plate carrier without it's plate is just some camo cloth.
This also brings up the PVP question. Zero already brought up his points but I'm curious how others feel about handling PVP we've always worked on a system of let the players choose. We've never forced rolls onto people unless they felt they wanted them, or if they were argumentative with basic actions. The rolling system isn't complex enough to be totally fair obviously, not without stat modifiers and bonus's for people and that seems like something impossible to really work in well to Gmod RP anyway. We've always kind of let the players act it out and controlled from the background making judgment calls in the end if there was an argument (Which to be fair was actually pretty rare!) Most of our players were always pretty good about being fair in a PVP fight and not powergaming, but also understanding their own characters weaknesses. I still feel this is kind of the best situation, I don't know if creating a complex system of stats and the like would be needed if we can put the expectation on the players that they are here for the same reason as everyone else and to play fair. I don't mind popping into a fight scene and moderating it and letting people know when I feel they've powergamed or gone too far, it's obviously human nature to want to win a fight in anyway possible which may make you do something without realizing it. In the end though I'm not sure that's the most fun for the players and I want to make sure you guys get a system you enjoy as well!