Make the epics and legendary dust-craft cost less, epics to 300 dust and legendaries to 1200 dust, both a 25% decrease.

Instead of making packs cheaper or giving out more shit, Blizzard should try to rework the dust system, it's totally neglected and unless changes to cards come, no one except the pros and those who dump huge amounts of money uses it regularly.
The jump from rares to epics is too big and because legendaries are 1-off cards they completely bottleneck who can play what decks.

If legendaries and epics are the cards Blizzard has determined to be the super-crazy-fun ones then they should be more accessible to players who have put in the time and money should only be a real incentive if you are new.