Man, I'm excited/nervous for Heart of the Swarm. I want to play the new campaign (despite the Wings of Liberty campaign being kind of meh) and check out the new units, but I feel like I'm just hitting my stride w/ WoL strategy and now in a few days everything will change. I've been watching a bit of the Intel Extreme Masters HotS tourny this weekend (here), and one thing I keep hearing is that ZvZ is looking to be nothing but Muta showdowns I'm not crazy about the Viper, either. I do look forward to the return of mass Hydra, which was deadly in Broodwar. You can't really go mass hydra in HotS, but Hydras are at least useful now. Swarmhosts look cool, but so far it seems like they're pretty useless in the meta-game.