Don't tweet late at night - SPAWNER buildings should not be a reliable defense. They should be something fragile you need to protect. Of course defensive towers like Tesla or Cannon should be a reliable defense against Hogs and Giants.
We can playtest for power, but its really hard to predict usage. Playtesters might say "hey this feels much better.... but I wouldn't put it in my deck" and we think "well great, its much better for the people who want to play it, maybe it jumps from 1% to 5% usage and that's good." But Goblin Hut jumped up to 20% right after, which is way too high for a card of that role. The winrate in testing wasn't that high, but its hard to predict how people will use a card, or what new decks will emerge with it.
Why not emergency nerf? Well, because we don't know if its an emergency type of problem - the usage has been trending down and hit 13% yesterday. That's still high, but hardly a panic situation. We can take the month to prioritize changes to spawners to make sure they are valuable but still leave space for counterplay. I think this season will just lean a bit heavy on Poison/EQ and we can expect some changes next month. It feels good that we are getting closer (to knowing how spawners can find a place in the meta), now we just need to pull back on what makes them difficult to counter.