I've tried imagining face vs anything else, I wonder if there will be any volunteers filling the face.
Teams are much better options, but it WILL be a nightmare to GM unless you put separate threads for them to communicate within teams (that would require gentelmen agreement of no peeking (or peeking allowed only to hackers that tapped onto other teams communication))
If you go with teams brawls - you could devise other than last team standing scenarios but capture the flag (ie. scientist in the compound) before the other team, where teams fight not only between themselves but also against environment.
Other way (one vs one or last man standing) if you ban spirits or drones I'd suggest closing the matches to a single class. ie. close combat vs close combat, ranged vs ranged, drones/spirits vs drones/spirits. That way, you can allow phys adept go against cybered close combat sam or rigger with unlimited number of drones against summoner mage or a gun adept against combat mage.