It's never going to be played outside of decks that somehow cheat it out, and even there its probably always possible to find a substitute that is just as good. The game has evolved since it was viable. Now every deck has gratuitous draw or card generation, so dumping your hand in order to clear one board is basically always suicide.
Deathwing is one of those cards that you're happy that it's in the game and you can randomly get it but it's not worth crafting yourself or even possibly ownign a copy of it, especially if it's a golden copy and you could use the dust to get something better.
I also have him in golden and I will never dust him. I know he is not good and might never see other than a meme play. I just don't have the heart to destroy him. Also his animation was updated and I just love when he attacks and "All will burn!".
I always keep my legendary cards. I have golden deathwing and never played him in a deck. Similar to when I got golden gonk and tess. If I ever need dust sure I'll dust em but I always seem to be sitting on 10k dust