Dated Aug 23, 2013, Here is a brief IGN interview DeeJ from Gamescom 2013. It includes discussion of the UI design decisions, classes, weapon slots, weapon customization, and a few other small nuggets.
In this video DeeJ reiterates that your entire character carries over to all aspects of Destiny. Including competitive multiplayer.
-
I think one of my favorite design decisions in Destiny is the minimalist UI. It's such a change of pace, I like it.