I've been playing Breakpoint and have been really enjoying the immersion and mechanics in the game.
I love running around with a buddy in co-op taking down the enemy bases but I was thinking it could be fun if you could invade another players game (or they could invade yours) as a hostile and hunt them down.
Obviously this should be an option you can have on or off.
When you join a players game you could have it so you can only see the area of the map the other player is in (sinking country etc.) and not their exact location. This could hopefully add a level of tension to the game as at any moment you may be required to fend off another player if they've joined. Again, there would be a warning on the players screen letting them know someone is after them. They could possibly gain more materials or resources for killing the other player (more rewards for the player invaded over the hostile player) but neither one loses anything from being killed.
I would like to play this anyway and see it as a simple enough addition to the game considering players can join in a co-op environment as it is.
Just my thoughts.