More noodling from me about that game no one else seems to play. Well, I've noticed a couple people well above me in rank this month. I'm still down at 17/18 in part because I lack a lot of cards, notably the quest cards. So let's start with that.
The quest cards appear to be quite powerful, possibly OP. Comparing their impact on a game with an ordinary legendary they outclass pretty much every legendary. The good ones (rogue, warrior, shaman) synergize with a deck type that would be competitive anyway and thus become extra-dominant. The downside to this is that having them is becoming nearly mandatory, which makes getting into Hearthstone right now super-expensive. I have some dust but not enough to craft all three. I don't recall Hearthstone ever having this high of a cost wall before and it's sort of cranky-making.
That said, it's entirely possible that this expansion has revived midrange decks. I have seen several variants of midrange hunter reappear and seem to be fairly competitive. Paladin still hasn't produced a really good midrange deck but I suspect that'll come too. Priest seems to have been the worst hurt by this shift, having tumbled from top to bottom of the competitive ranks. The priest quest is weak (and too slow), dragons are dead, and people are still experimenting with tempo (priest is bad at this anyway) and gimmicks.
Pirate warrior is still a thing, but since the warrior quest is so powerful you're as likely to see taunt warrior now as pirate. Sadly, classic control warrior is looking dead simply because it's inferior both to pirate and to quest/taunt.
Jade decks are still prevalent but are generally inferior to the quest decks. Jade shaman is decidedly worse than quest shaman, having lost half its opening game in the card shuffle. Jade druid still seems to be the thing but I suspect we'll see beast face druid come back soon - the class needs something faster to deal with the rogue and shaman quest decks. I'm still experimenting with my jade rogue; since I don't have the quest I need something. The variant I got last night seems not to be utterly sucky.
Zoo is still zoo, as expected. It has probably the usual 50-ish percent win rate. The problem is that if you face a warlock you know right away what you're playing so the mulligan and early plays become obvious. That alone forces down their win rate. I've seen a couple attempts at midrange and demon warlock but nothing good yet. The other problem is that AOEs have become somewhat stronger; murloc shaman has ways to avoid the cheap AOEs but warlock AOEs are too self-destructive (I think).
April is just a crazy month for me so I'm not sure how much more ranked play I'll get to do. The next big checkpoint will be seeing what decks the high-rank players bring to the tournaments. I predict 3/4ths quest decks.