I've only done about 2/3 of all the Strikes in the game so far all the people I've been matched up with more or less clear all the mobs in the game. The 1 exception to this rule is the Devils Lair. I've only done that mission once ( back in the Beta ) where everyone stayed behind in the first area to make sure everything is dead. Nowadays everyone hops on their Sparrows and speeds past the first few mobs of bad guys.