having one character from each class not only lets yo incorporate different play styles into your game, but once each character is leveled how you want, you are ready to take on any task. say you are going into a Strike or Raid and there are more Warlocks and Hunters. you could bring your Titan to provide defense. or say that there are more Titans and Warlocks. your Hunter could provide sniper cover while sneaking in to do extra damage on bosses with their Invisibility Cloak. it really just depends on how you play, but from the beginning I created one of each class for just this purpose. it IS a bitch leveling up all three characters, though. keep in mind the grind time you will need to maximize a new class.