I may have just missed this, does anyone know if they've shown or said what happens after HoW when you dismantle equipment? I ask because we aren't going to need non-exotic shards or energy, so if I dismantle a 365 attack weapon will it provide me with etheric light?

They haven't shown or said anything as far as I know, but I won't be surprised if they continue to give ascendant materials since you could still have guns and armor that would need them still, and because the Speaker will have an exchange for them.

I think that'd be strange though since all exotics after the previous expansion dismantled into exotic shards. I think it'd be strange to dismantle into ascendant/radiant materials when no new weapons will require them. It's true you could trade them for currency or motes, but you wouldn't be able to trade them for the etheric light so I think it would make dismantling even less lucrative than it is now. Maybe it'll only drop etheric light if it's fully upgraded? Or maybe only have a chance?