The newest announcement out of Hearthstone is a series of nerfs to core cards from the Classic and Basic sets. Blizzard wanted to fix some particularly defining or problematic cards for all time and so they swung the nerf bat at a bunch of offenders. The short version is that they appropriately nerfed a couple of the most important aggro cards, (Leper Gnome and Knife Juggler) smashed druid Force/Roar combo in a sensible way, and made a few other reasonable changes to some stuff that prevented a lot of interesting new things from happening.
Oh, and they flew a giant spaceship over and nuked Big Game Hunter from orbit. Because that is the only way to be sure.
But this is Big Game Hunter. It might be the only card in Hearthstone that could survive a 2 mana increase and still be used, and a lot of people seem to think that is true.
I think they are wrong. That is, a couple of people will still use it, but it will cease to be a significant consideration when building decks. Blizzard decided to utterly annihilate BGH and they weren't going to take any chances on missing.
While BGH is still good in the situation where your opponent drops a 8/8 minion and you need an answer he is now *horrendous* when there is no target for him. A 4/2 for 3 mana is poor, but at least it will kill something. It can be played on turn 3 against an aggro deck and kill a minion. Weak, but not disastrous. However, dropping a 4/2 on turn 5 is game losing. BGH goes from an amazing tech card some of the time and a weak some of the time to a good tech card some of the time and unusable garbage some of the time.
People will soon realize just how important his cost was, even when he is killing something. On turn 8 when you use BGH to blow something up you used to have 5 mana remaining and now that is reduced to 3, which is a huge amount of tempo lost. BGH was enormous precisely because he was so amazing in terms of tempo - you could often do something really useful on the same turn you dropped BGH to blow something up, and now that is quite unlikely to occur. You probably just get to kill a thing and play a small 4/2 minion.
I wish they had done something different with BGH, like change his instant kill mechanic to something like "do 4 damage." However, this accomplishes what I hoped it would - big minions are no longer going to be measured in the shadow of the dwarf with the gun.
It is obvious that Blizzard is trying to make big minions more worth it. With the nerfs to BGH, Owl, and Hunter's Mark they are taking steps to get rid of all the random cards in the game that destroyed huge minions by accident. If you want to wreck big minions or silence them you will have to make actual deck sacrifices to do that. There aren't any things you just toss in because 'why not?' anymore. If you want to have your answers to big minions now you will have to pay for it, and that is going to shift the "big minions - hard removal" equilibrium a long way towards the big monsters side.
All of which I like. Honestly with the way the hunter drops are going right now I will likely be going after a control hunter build when the new expansion drops, so I like this shift to a late game style. This change to hunter feels calculated - Blizzard knows the Hunter hero power is garbage for control so they can release really powerful mid and late game Hunter cards without worrying too much. I hope they get that attempt right!