Ben Brode just announced some big changes that are coming to Hearthstone's next expansion.

• No more duplicate Legendary cards. Once you've crafted or obtained a certain card (gold or normal), it isn't possible to obtain again until you've earned all the legendaries from a set.
• You will get a guaranteed Legendary within the first 10 card packs of a new set.
• It will not longer be possible to open more than 2 of a Common, Rare, or Epic card out of a single card pack. You can still obtain dupes in other packs of course. (This means it will not be possible to get three fiery bats in one pack)

Next expansion will have 50 Legendary cards, confirmed

Interestingly Overwatch is also getting rid of duplicates through loot boxes. I guess the Blizzard analysts have decided it is a beneficial thing across the board.

Really? that's good to hear, hopefully they roll this into Heroes of the Storm soon too. Tho I suspect it might take a while, since loot boxes are a recent thing in HotS in the first place.

YES!!!! Nothing worse than getting a duplicate Legendary....

Yeah happy with these changes, the amount of duplicate legendarys i've had.. that 400 dust is the worst kind of 400 dust!

Price bump coming to the US soon to compensate.