I still dust all the gold cards I get, and I get a lot of common/rare duplicates even though my collection is small. Dust will come when it comes! If I dusted Grommash (not going to) I would have 800 dust right now. Basically, I realized that most of the cards I want to craft are common/rare. But if I keep dusting epics/rares for commons/rares, eventually I'll just have a ton of duplicate commons/rares to dust, and it will be a net loss. I'm going to play the long game here. I have 300-something dust right now just from dusting duplicates and gold cards.
Now, if Grommash was gold, I would have dusted him in an instant. :-D
An epic, 2 rares and a Legendary all in one pack? That's a god pack! Was the Legendary on the top of the pack? That's the Xerxes spot.
Grommash was the 4th card.
I agree that some cards will always see play. But with just 2 weeks left till the announcement I just don't think it's a good time to use your gold on packs. I fully expect that the new set will have a much larger impact on standard than the classic set will. So in my opinion unless you really want cards now just hold on to your gold these 2 weeks and finish up some quests because there is a big chance the packs for the new set will have a much higher chance to give you playables than classic packs now.
My main deck is Zoolock, and I'm retaining 90% of the cards I need with the expansion. I'll just craft the handful of cards that are optimal for Zoolock play, and then go back to buying packs.
I wish I had Grommash in a pack. My first legendary was Gruul. Dusted him for Velen.
Since then I got legendaries pretty reguarly. Ragnaros, Malygos and Jaraxxus were the most useful. Also got Greenskin, Varian, Sky Captain what's his name, Iron Juggernaut and a Golden Velen among others. But my best legendary was a golden Hemet out of an Arena reward pack.
I know Gruul doesn't see play, but he seems like he has potential. Maybe he should get +2/2 per turn.
I would love to get Malygos for a Shaman deck.