Definitely more to it than deathmatch.
For one thing, there's no official deathmatch game mode (though I suppose the Arena game mode comes close). Each game mode has an objective, such as capturing a flag, or claiming and/or holding territory. Also, as the game's title might suggest, teamwork is quite important; every class has its' strengths, weaknesses, and ideal role. A well balanced team with good teamwork will generally achieve map objectives more easily.
The game can definitely get chaotic, such as when there are lots of players (16 vs 16 can be utter pandemonium). But even then there's an order to the chaos. With fewer players, such as 6 vs 6 or 8 vs 8, serious strategy and tactics come into play.