Hearthpwn

Try mine, https://www.hearthpwn.com/decks/1233850-spirit-of-the-dragon

I think the idea here is to get people to invest in crafting the hilt for the reward. I know its an old design and the artwork is also old but I thought it would be a good way to incorporate spirits even further into the game. I'm also not sure if there are any legendary weapons from the classic set, but this sword is more from Lich King lore. I remember doing the quest in WoW, and I looked up the card in the search bar and it seems to have been used in some sort of gameplay at one point. Maybe it could be re-introduced?

The overkill mechanic is difficult to achieve with the hilt because it's a one shot or nothing type of deal. You'd need to buff the weapon in order to achieve overkill and the reward. I know there are cards that bring weapons back to your hand and such, but you could also get the hilt back and might not have the weapon buff cards. And using your opponents spirits against them seems interesting. 

Anyway, I just like the idea of a classic set legendary weapon. I think the weapon into reward mechanic is cool too. Plus there is lore behind the weapon. The devs could use new and improved artwork but this artwork was made by Joe WIlson, who made loads of other artworks for still in-use cards. 

Rumble calls for weapons!