I never played D1, but from everything i'm hearing people love the raids from that game and are finding the current ones very lackluster. So my idea is why don't we try and re release the raids with SOME new mechanics, secrets, hidden sections, SOME of the original loot that we are missing in D2 and on top of it all hours upon hours of content people are (nearly) guaranteed to love.
My understanding of the story is very limited, but from what i've seen of the darkness it is totally possible for guardians to fight previous enemies in previously used arenas and I think that using this ability to let us play old well loved raids would be awesome. The time Bungie would have to take to do this is lowered considerably as they aren't starting entirely from scratch.
I'm new to the forums and hope this post can get some replies and exposure as im really interested to see what people think of this and what the plausibility of this idea is. I realize that the game is increasing in size and takes up a lot of space, but i'm honestly willing to give up a hard drive to achieve this level of awesome content and storytelling.