All I read in this is "Whaaaa! We had a contract to deliver a game by a date and couldn't do it, so we had to cut a bunch of stuff. Blame everyone but us!" I mean, yeah it sucks they had to trim the game to the state it is in, but that isn't Activision's fault. Bungie said they could deliver their vision by a certain date and, after some internal problems, couldn't. Is Activision supposed to just be like "well, you couldn't originally finish what we agreed upon, despite our paying you, here is some more money and a longer timeline!" No. That is just bad business.
That AMA really points to bad project management within Bungie.