Hearthstone 24: Don't tell the others, but I'm rooting for you!

[Thomas Cardew]

Rarity and dust values mean nothing with cards you're guaranteed to get. They only matter when you need to either get the cards from a pack, where they determine the odds of doing so, or spend dust on them, where they determine the cost of making them. Moreover, all that gold value that you're giving up you wouldn't need to give up if there weren't new cards in this mid-expansion adventure. It just amounts to less cards from the expansion that you can afford to buy over time. And if it goes over well, which it probably will, it will become a regular thing, and thus you'll just have fewer cards from every expansion going forward. If you're like me and weren't ever accumulating all of the cards you'd like to to begin with, that looks pretty darned awful and unreasonable.

Alternatively, if there are 5+ cards I want in an adventure, at least 1 of which is legendary and 1 (2 copies) is epic, it is SIGNIFICANTLY easier for me to get them with adventure than by buying packs from the expansion. I'm guaranteed them and bunch of extras, which I may or may not want. If I spent the gold on packs the odds are that I wouldn't get the specific cards I want and instead got a collection of dust to craft with. This would leave me with 400 dust for the same amount of gold, if I wanted two copies of another epic I would be down 400 dust.

I would personally prefer it if EVERY expansion was just an adventure because then I'd actually get the stupid cards I want. For example, despite all the classic packs I've bought or be given over the life of the game, I still don't have the Black Knight, Ysera, Antonidas, or Tirion. All cards I want but have never pulled because the chance of me getting the cards I actually want from packs is so absurdly low. I do have Gruul, Lorewalker Cho, The Beast, King Mukka, and Deathwing because those are the useless legendaries I've gotten in packs but refuse to dust. If if I dusted all of the stupid legionaries, I'd get ... 1... card I actually wanted.

There's basically no difference between this adventure and releasing more cards in the initial expansion. But even if you started saving just when the expansion dropped after 4 weeks you'd have 1400g for doing dailies (4*7*50). That leaves you needing 1400 gold to buy everything, or 14 packs worth of opportunity cost that you didn't get to buy in advance if you saved up. Essentially the opportunity cost is that you don't buy packs for month in advance. Alternatively, you wait a month after the adventure drops to get everything just like if it was a new expansion and you didn't get the cards you wanted in your initial pull. Realistically far less time than that because you should be winning games, getting the free 80g from friends occasionally, and rerolling for higher value quests.