Discover:
Cards that Discover from a random pool no longer apply a class bonus. As Discover pools have gotten more specific, some are too narrow and repetitive. This change will increase the variety of cards from random Discover pools
Looks like Stonehill just got nerfed in Paladin. You can also hope for crappier mech choices on Boom…
Source: https://playhearthstone.com/en-us/blog/23097372/hearthstone-update-september-10-tombs-of-terror
Does anyone know how to put this in an example?
What I’ve interpreted from this patch is that there has always been at least one class card option, but now there is a chance that they could all just be neutral cards?
Correct me if I’m wrong, because my previous guess was that you can no longer discover class minions, and that seems too much of a nerf.
I still want to discover my Tarim from a stonehill, occasionally.
Before the patch, all cards that were eligible (neutral cards and class cards of your current patch) were in the pool, but class cards had an extra high chance of being offered.
After the patch, all cards that are eligible are still in the pool, but all with equal chance of being offered.
So playing Stonehill Defender as Paladin should still allow you to find Tarim or Tirion. Just not as often anymore.
Before patch you’d see class cards 4x as much, now every thing is equally likely. So you can still get Tarim but it’s WAY less likely. You’d think i’d just be a quarter as much, but because there are way more neutral taunts it’s actually gona be considerably less than that.
Yup, class cards were offered 4x as often. Because Pala had few taunts, there was a high chance of getting Tarim/Tirion
Rip my trollock, no more consistently of discovering juraxxus from discover demon cards
So…mage and rogue discovers are still great
Then in that case, I wholeheartedly support this nerf! More chance to (quite literally) discover cards that I didn’t even know existed.
Who knows what secrets we’ll uncover? 
You’re still quite likely to find JARAXXUS, just less often. In Standard, there are 26 demons you can discover (8 neutral). Wild adds another 21 demons (3 neutral).