Guys, the sky isn't falling. People were underprepared for Workshops. Yes, something probably needs to be restricted, but in the Article I'll be writing I will be writing a clear argument that it is NOT Mishra's Workshop.
Culprits: Phyrexian Revoker, Foundry Inspector, Walking Ballista, Arcbound Ravager.
Those will all be cards I talk about. Relax though, and have a good sideboard plan, and we'll get through the Shop Dominance.
I don't think anybody is panicking (e.g. "the sky isn't falling.") Shops variants have been a large portion of the meta for years now. Whether or not people are "prepared" to play against workshops is a tangential issue. The main concern, as you alluded to with your culprits, is that Shops decks are improving at a faster pace relative to other pillars of the format.
Cut a head off the hydra (restrict a card), and two more grow in it's place. Newer, better, more aggressive cards continue to be printed. The acceleration of shops is outpacing the restrictions.