We've already established that a turn 1 win via Earthcraft is not easy in Type I. I would think it would be somewhat more difficult in 1.5. Turn 3 sounds like a more common clock for it, with maybe turn 1 being possible with some insanely lucky hand... I don't think that it could be faster than Dragon. And Dragon wins by dropping an enchantment to cause a loop. Its other permanents are typically lands/artifacts. Earthcraft would usually need components that are all enchantments, making it pretty hateable (Disenchant effects will have more targets to shoot for).