The key here is to glean from a few hints that Bungie and Deej have been dropping over the last month. When HoW came out, the fine print said something like (paraphrasing) "Etheric Light will bring any year one legendary weapon/armor to the maximum obtainable attack/defense obtainable in year one." Which, if you speculate and read between the lines, means that Etheric Light will not ascend gear to Year 2 levels which is what they are considering The Taken King to be the Kickstart of. Then you go to the IGN interview yesterday with Deej who said when asked about increased vault space again (paraphrasing) "A key element to destiny and defining your character is having to make choices as to which guns and armor you keep and which ones you discard". While this one is a stretch, he may be trying to ease us into the right of leaving our old gear behind. My personal belief is that exotics will always be upgradable but legendaries will get left out in the cold. As much as I'll miss all the amazing VoG weapons, especially after using them again post ascension, I do feel like letting them go and adopting new weapons is a good thing. I got used to TDB weapons when VoG were old news, I can do it again.

This+

I agree