Nerfs incoming! I'm kind of happy about these, mainly because they don't affect me (negatively).
The Shaman nerfs will help a bit, though I'm not sure if it's really enough to deter Aggro Shamans - at the same time they can't really do any more without just killing Shaman, I suppose. I would have gone for Tunnel Trogg instead, maybe something like "Gain 1 attack for each Overload card you play" rather than per crystal.
Call of the Wild nerf is fine, I don't play Hunter, I don't like seeing that card when I'm already losing.
Execute nerf is probably the one I am least happy about since I play Warrior most, but I guess it's a fair nerf. The Charge nerf (buff?) I support, clearly aimed at OTK Worgen.
No opinion on Abusive Sergeant.
Aaaand probably the most controversial change - Yogg's Battlecry! I think this nerf is insane and hilarious. I don't play it so it won't affect me, but this absolutely kills Yogg (like the way he always kills himself). I can see him thrown in a few fun decks still, but I don't think there will be many Yogg-centric decks after this.