Unfortunately, Burch didn’t say much about the upcoming story driven downloadable content. He did, however, mention that there is even more DLC coming that won’t be included in the seasonal pass system.
Oh, he also mentioned how much fun it was to write for the Mechromancer. This delights me to no end, as I look forward to playing her when she’s released on October 16th.
I highly recommend watching the interview section of the video. In it, Anthony Burch humorously talks about his career (or lack there of) and how he got hired to work on Borderlands 2. Burch also talks about his influences for Borderlands 2, which makes total sense upon retrospect.