Hearthpwn

''Summon Pet'' now cost 2 mana instead of 3 mana. Small buff.

Small, but significant. With the newly charting big-beast deck, that one floating mana cost makes all the difference. That point where you'd normally be tossing a HP into an opponent's face for 2 damage can become a Huffer for 4 or a Leokk for + damage to whatever your board is. Long/short: Very solid hero for the current meta.

Wait, if we choose Improved Explosive, can we play vanilla Explosive Trap etc.?

You can, yes. They are treated differently. It does cause for some unusual interactions that I'm going to have to check a few replays to make sure I understand what's going on... For instance, someone can have a minion attack your hero, and trigger both Freezing Trap and Improved Freezing Trap. I'm not sure if the increased costs both stack, or if only the first one applies. Same deal with the Freezing Trap cost increases.

Summon Pet

Improved Explosive Trap

Improved Freezing Trap

Improved Snake Trap

Improved Pack Tactics

Improved Open the Cages

Improved Ice Trap

And the last one is a card that hasn't been revealed yet at the time of this comment, so now hunter has a spell counter of sorts (though since this is an improved one, the actual card will probably only increase the cost by one).