On the Darkness (from the gameinformer article):
I feel like Luke Smith has been misquoted here. He didn't say that they are dropping the Darkness, rather that they are focussing on the Light right now. The Darkness is an important part of the universe of Destiny.
And on the Exo Stranger (from the PCGamer interview)
This doesn't mean she'll never be in the story again, Luke Smith is not the Last Word on that matter