We have two competing philosophies about corner cases for cards like Small-Time Recruits that sometimes dont do anything: first, cards should progress the game towards a conclusion if at all possible, and second, cards should do what their text says. In the early days of Hearthstone, we tended to err on the side of favoring the first philosophy. More recently, weve seen that our concerns about games lasting too long because of situational cards havent been confirmed, so we usually lean towards the second philosophy. We keep both ideas in mind, and tend to evaluate cards like Small-Time Recruits on a case-by-case basis.
Hearthstone is boring when neither player has stuff to do. The situation where neither player has minions or spells to play is rare, but does happen occasionally. Fatigue will end those games, but having to sit and wait around for fatigue isnt fun. So, our general preference is for cards to do something to help end the game, even when theyre otherwise situational. Thats why, for example, Sense Demons grants players Worthless Imps, and why you get a Shadow of Nothing when you cast Mindgames and your opponents deck contains no minions: getting those 1/1s forces the game to a conclusion.
On the other hand, we think cards should generally do what they say.* Its weird when you have a card that says it does one thing, and then when you cast it, it does something else. Wild Growth is the most famous offender of this philosophy. When you have ten mana crystals and cast Wild Growth, instead of an empty mana crystal, you get a copy of Excess Mana, which you can then cast for a card. This is in keeping with the idea of cards should do stuff and definitely prevents the feel-bad moment of drawing Wild Growth when youre capped on mana and not being able to do anything with it. On the other hand, card text secretly changing in that way is weird and is contrary to the idea of Hearthstone cards as physical objects.
We were most worried about games bogging down with do-nothing cards when making the Classic set. Before release, we thought that Hearthstone games would generally be fast-paced, but we couldnt be sure. So, the Classic cards tend to have more safety valves to make sure they still have an effect in corner case situations. Were now more confident that the presence of a couple of situational cards wont bog down games too much, so we dont feel as compelled to make sure that cards like Small-Time Recruits always gives you something. For cards that grant mana crystals, though, we have accepted the precedent of Wild Growth people have grown so used to getting Excess Mana that it feels like a bug when they do not. Ideally, it would be more obvious when cards are in their corner case phase thats caused their effect to change, but because were talking about solutions to corner case issues, we havent prioritized finding an elegant solution for those cases.
*Im not going to open the Molten Giant can of worms, which is more of a templating question as opposed to a functionality one
