Out of curiosity what makes you think that questions will get answered and threads closed in dlc for D2, if those same questions weren't answered in D1 with all its dlc? I think you're right about "filler" but I think it's purposely designed to create a narrative that's easy to follow for anyone playing and new to the series. That said it actually changes story apparently so there really isn't any reason to believe they will stick to something from the first game at all. I skipped rise of iron in D1 but apparently I keep reading that at the end you, as the generation of "young wolves" become iron lords and then in D2 it's back to just one dude and that part is sort of ignored. I don't think bungie even knows where to go with stories at times, remember taken King, which seems to have been the most popular expansion was actually in the vanilla game but cut out at some point of production.