I believe this card needs to add to the casting cost of spells instead of multiply it. That way there is no particular bias towards one spell over the other. If it makes spells cost 3 more or something, that would be fine, but double makes cards like Fractal, Parallel Universe, Miracle, and Antimatter far from playable, while it hardly touches Protect Artifact, Animate Weapon, Thunderbolt, Chaos Seed, Stone Skin, Deflagration, Siphon, Fire Lance, Ice Lance, etc.... This only really hurts expensive spells, where a flat increase would slow down every spell-based deck.