Some players in China are even experimenting with a Rogue version that runs the quest only to benefit from those quest support cards, not to complete the quest itself. This might push it to be a real tier deck, you never know.
DO NOT DUST ANYTHING. Even if this card wasn't amazing, which it is, there's literally 0 reason to dust anything. First off, you get 1/4 of the value. It's literally like trading your games to gamestop lol. Second off, most of the people on this game who DE stuff just use the dust to craft stupid tier 1 garbage, which makes the game crappier for everybody. You're going to get bored playing that crap after a day, trust me. Build your own decks. Experiment and actually play the game to have fun, not win. Be an individual!!
Kragg is obviously better suited for Shaman and Hunter than the other classes, and useless outside of (side-)quest decks. And the future of quests is hard to estimate.
Still, it is a substantial support card, and likely appears in any Hunter deck with Clear the Way throughout the next year, and maybe some other classes find use for him.
As Bob likes to say: It's not the strongest, but it will fight hard. Certainly not the flashiest of all legendaries, not the enabler that will make any quest deck super good, but I would not be surprised to see it a lot for quite some time, especially once Zilliax leaves the format.
Is it good... are you gonna play it... is there a world in which you are going to play it... do you play quests... these are my questions I ask myself. As someone who does dust cards- legendaries included- I have to weigh these options. I eventually had to dust my Malygos b/c I realized that I HATE OTK decks and thats all Malygos is good for. Its a great/ amazing card but I'm never gonna play that way... so why should I keep her. As for me... I like Kragg b/c I play quest decks and its fun that way.