Does WoTC know what decks ppl will play while they're playtesting a new set for MTG?

Usually, they have some idea of what the decks will be, just because they make the cards and watch how the Pro Tour events play out, so they can predict what will happen in general. But they probably miss one or two good decks at times just because they didn't anticipate a particular card combination. Like with the recent banning of Stoneforge Mystic. They printed her with the intention of her languishing in obscurity throughout Zendikar block, and then become good in Scars of Mirrodin, and then become really powerful at the end with Living Weapons, most notably Batterskull. What they didn't expect is for Stoneforge to combo with Quest for the Holy Relic, Squadron Hawk, Memnite, Ornithopter, etc, making the brutal CAW Blade deck even before the Living Weapons hit the ground.