It's easy to blame a lot of this on Activision, but I think Bungie has shown that they are no longer a competent game studio. I think the biggest joke is the way they made us grind to level up our old gear with Etheric Light in House of Wolves, only to render it all completely obsolete in The Taken King. I'm not interested in losing all my progress at once just because they can't figure out how to gradually introduce more attractive options. And as you pointed out, all the old content is obsolete now as well. I don't know if they lost some of their good developers or if they're just out of their depth with a social RPG (Halo is a lot simpler). Either way, they don't have it anymore.