Watch_Dogs battle royal would have a huge potential on being different, by using the mechanics from the series. Name of the game would be stealth and blending in.
There would be NPC people walking on the streets and NPCs driving around, just like the game has. However, I would make the law enforcement stronger and more aggressive to discouraging run and gun gameplay. The weapons and gear should also be world spawns and limited on how many different weapons you can carry. Just like in the original game, if someone sees you doing illegal things, they call the cops on you. While they could still be scared to not report you, going after witnesses would increase the likelihood of other players spotting you.
The other specialty that Watch_Dogs would have is hacking. You can cause chaos around you, or try stopping your pursuers with your skills. There could also be new BR specific things added like mainframes that reveal the next safe zone to you or if you fail the hack shows your location to a few closest players.
Taking out the ctOS in the final circles causing a blackout could be very powerful if you are the only one with night-vision goggles or seeing someone coming around the corner on a camera you hacked could save your life.
With the increased threat from law enforcement, you also might be able to find high-risk places to hack to clear your wanted level.
It could work in the existing map, but maybe some interior spaces could/should be added. Watch_Dogs even has the perfect excuse for the ring closing-in, it’s ctOS scan coming in, and if you are in it, the (NPC) law enforcement will know your position and will close in fast.
Also to incentivize not shooting people, environmental kills could be worth more on top of (maybe) being more stealthy.
Obviously, the idea isn’t complete and it assumes a lot of knowledge about the Watch_Dogs franchise and Battle Royales. I would love to talk more about it, regardless of if it ever actually gets made, or even seen by anyone with the power to do anything with it. But, it’s something to get you thinking, isn’t it 😉