Have I mentioned Urban Terror? Yes, oh well I’ll mention it again. TS (execution) is the pretty much the main comp game mode in UrT now. The next season is about to start and TS has twice as many sign-ups as CTF or Bomb, and the only active ladder left on Clanbase is TS.
You don’t need to add objectives, either via C4 or invincible revivable team-mates, the beauty of TS is precisely it’s simplicity, it’s pure team-work, pure fragging, nothing else getting in the way, can be played with any number of players per team and has that easy to understand yet hard to master aspect that is great for comp both from the players and spectators point of view.
The only real mechanic you need to add is to make draws impossible or hugely undesirable, such as declaring the winner the first to win “x” number of rounds, rather than play a fixed number and having most of them drawn because neither team dared risk making the first move.
The fact you have Medics, and can revive and self-revive, gives XT’s implementation of this simple game mode it’s unique flavour, and I can see this mode actually being quite popular.