Get to vanguard rank 3 and save your strange coins for exotic items
That's how I aquired all of my legendary/exotic stuff so far, that and the Queen who felt it her duty to grant me 3 pieces chest armor and 5 helms...
I loot system for in game playing sucks balls, I have yet to get a legendary engram drop since hitting lvl 20. The two that I got before that yielded me items for classes I wasn't using