If you're still missing any significant number of cards that can commonly be used in top tier decks of a certain archetype, or class staples like Antonidas or Tirion, I say dust it. Deathwing is incredibly frail when stacked up against other bombs, wiping the board is easier in other classes and in that scenario you often get to repopulate it just as a fast with something stickier. At 10 mana you die from the hand pretty often as well (Freeze Mage burn, Druid Combo, Patron warrior one billion damage, etc...) and you can can get repopulated on pretty fast if they didn't just overextend into it. Even in that case, most decks, aggressive and control alike, don't suffer from a strict board wipe as hard as they used to. If it doesn't have deathrattle, it already got it's advantage out there, cause that's a design in Hearthstone that consistently generates good cards. The last thing you may use it for is dragon deck synergy, but depending on the deck you can get away with Alextrasza, Ysera, and/or Nefarian on the top end, and failing that I'd probably play Chrommaggus and Malygos over it.
tldr dust it unless you're going for completion. You can find another card to play over it for any niche you're thinking of.