The drake is also a source of fury and, if you're on your last legs, a transfer target. So don't forget those two factors when you're weighing them up.
As for your idea, you'd be hard pressed to have a cloud wall up in front of your heavies, since you'll want to run early on and gobbers can't run and smoke. But the krea gives you access to 2+ bubbles (krea, warcaster and a cyclops shaman if you brought one for the list) which you won't outrun. So personally I'd lean krea over 3x gobber pairs, but if you could squeeze a gobber unit into the list then whoever they get with their smoke (like your caster) could be +4/+2 which is a nicer swing