Mech? Low DPS?

That's to say early game which I suppose can make sense, but, and this is a guess, if Swarm Hosts spawnling units are light then Hellions make them absolutely useless. So even early game they have no tipping point, and getting Swarm Hosts is basically a form of "Zerg Mech" Much like with Brood Lords, a Mech Strategy is to get Hellions in the back to roast Broodlings almost cutting their damage off entirely while Vikings and Thors rip them apart. I agree with everything else. If Terran stayed the same it doesn't mean Terrans weaker, it means that strategy's will still change. Thats the core point you are trying to make.