Wooh! Can't wait to play around with the new set.
No, stoneforge mystic is terrible in Zendikar block constructed. What are you going to fetch with it, TRUSTY MACHETE?!?!?! Jace is obviously very good, but he is best in the RUG shell that Michael Jacob/the Channel Fireball team made for PT San Juan (Zen Block Constructed/ROE/ROE/ROE Draft). Other good decks were Eldrazi Green, Vampires, and UW Control. I would prefer Ravnica, Time Spiral, or some older format for Block Constructed as opposed to Lorwyn (yawn faeries) and scars (yawn tempered steel).zendikar block would be like uw control with stoneforge mystic+jace, allies and green eldrazi wouldn't it? innistrad block would be a tad limited, and scars is yawn tempered steel. shards or ravinca block might be fun? hell even shadowmoor would be worth playing except for that bitterblossom thing.