There's also a chance that Blizzard will release a downloadable version of Diablo II soon to their Blizzard Store. To be able to download it when it becomes available you'll need to register your keys through Blizzard's Store, shouldn't take long.
edit: but to go on topic again. I don't know why they didn't do this already. I guess the SC community is bigger then ours, but still there's plenty of Blizzards decisions where I think they went wrong with course of Dii.
Some people see in this a hint that a new patch will be released. And thus they want to get the newest patch in there on-line store form the beginning.
And if it comes, we probably won't have to wait very long as it seems to make sense to let it go hand in hand with the ladder reset. Or let it follow close after the reset.
Or they can keep it for the next reset, then it's waiting more then one year.