For a little while I had actually implemented that you could switch between teammates with the idea that you could leave them behind or order them to a certain spot on the map. They'll automatically attack anything nearby, so they'd be sentries guarding a corridor or something. With different unit specialties you could even have one "hacker guy" hack the consoles while the machine gun rambo defends in some safeish spot. This needs some work and thought, tho, but would be super to have in the game later on. :)