Design Breakdown - Discover

Hot off the presses from BlizzCon our good friends at Team 5 have a new Hearthstone expansion coming out _this_ Thursday! I'm excited for the design of a bunch of the cards they've released (which have all been revealed), but I thought I'd waste some ink here on the mechanic that they've added with this expansion:

Discover 

According to the powers that be "each time you play a card with the new Discover key word, you'll get to choose between three random cards that can be used by your class."

It's RNG

Buckle up, everyone... you're getting even more RNG in Hearthstone. When you step away from the vitriol that passes for conversations on other forums, you'll generally find that discussions about RNG in Hearthstone focus on whether or not a given instance of RNG is "good" RNG, or "bad" RNG. Good RNG enhances the game, Bad RNG makes the game frustrating. It's worth noting that there's really no such thing as "good" or "bad" in this debate; all instances of RNG exist on a spectrum, from a theoretical, perfect RNG to a polar opposite worst RNG. The question is where does Discover lie on the spectrum?

I think I can make a solid argument that Discover lies fairly high-up on the positive side of the RNG spectrum.

1. You get to look at 3 (presumably) different cards. Since there is a larger sample of possible results the variance is substantially diminished when compared to other instances where the results can be either the single worst or single best card in the subset of available cards. With 3 cards, the worst card you'll get is the 3rd worst option, but the odds of that happening are almost inconceivably small.
2. It increases the odds of finding more situationally useful cards. You get three choices, which makes it more likely that you'll find a card that is relevant to your particular situation. Since the RNG is more likely to be useful, it is better.
3. The cards go into your hand. Ram Wrangler is one of my least favourite cards in Hearthstone. The variance is huge. For your 5 mana you can get a webspinner or King Krush - a value from 1 to 9 mana onto the battlefield at the exact same cost. Now, even though the same subset of Beasts is used for Tomb Spider, the result goes into your hand and the cost of the minion factors into the choice that's made. This is far better.
4. You can't cross the class boundaries. It's very hard to balance the game when any class can get any card. Team 5 has made their jobs a lot harder by allowing this to happen elsewhere in the game, but they've quite rationally not made things worse by restricting the Discover options to your class or neutral minions.

Is it any good?

Yes. It totally is. However, you do pay a lot for the ability. Let's look at the two vanilla, neutral examples that Hearthstone has gifted us:

  

Both cards surrender 3 points worth of stats for the Discover ability (but add the Beast tribe, which is worth about half a point in stats). This is exactly the same cost that Novice Engineer and Gnomish Inventor pay to draw a card. Is Discover worth as much as drawing a card? The answer probably is "it depends." In most normal circumstances you'd much rather have a card from your deck; I mean, you put it in your deck for a reason, right? 

There are times, however, when you're in a situation. In cases like that, your deck may not have any outs, or maybe very few that you're statistically unlikely to draw. That's when Discover can maybe do work for you. Raven Idol exemplifies this: for a low cost you're given the flexibility of reaching out for a spell or minion, depending on your need at the moment.

There's plenty of space for the Discover mechanic to grow, as well. We can attach it to any trigger that can only happen on our turn; Battlecry, Choose One, Combo, and Inspire are good, but Deathrattle is out. We can associate Discover with other conditional effects, as well (something that no actual card does at the moment). I created Booty Bay Auctioneer as an exploration of where the Discover design space could go in the future:

My opinion: Discover consistently gives cards an effect the moment they hit the board, making it more practical (usually) than Inspire. It also contributes towards card advantage, which should continue to be a boon for control decks.

Discover Keyword Design Notes:

• Always Capitalized
• Always bolded
• When referring to a specific cost use "(#)-cost"
• Follows directly after a condition:
• "Battlecry: Discover a(n) X."
• "Choose One - Discover a(n) X; or..."
• "Battlecry: If X, Discover a(n) Y."
• Cannot be attached to a condition that might trigger on an opponent's turn
• Worth approximately 1.25 mana in most cases. More when the subset of Discover targets are particularly valuable, less when they are less valuable.