Instants are the backbone of Limited. This is where you find all those battle tricks I have lost Limited games against.
All I can say is countering a spell is a little more expensive in battlecruiser Magic. Compare Cancel with Disappearing Act. With Cancel, you pay the same mana and you counter the spell. With Disappearing Act you pay the additional cost of returning a permanent you control to your hand. True, if it has an Enters the Battlefield (ETB) bonus, that's nice. But what if it doesn't?
I wonder if Paradoxical Outcome can be abused?
Make Obsolete is your 1/1 token clearer, and Tidy Conclusion and Unlicensed Disintegration care about artifacts.
Built to Smash, Welding Sparks, and Incendiary Sabotage care about artifacts.
I would have prepared the simplicity of Naturalize for the extra mana I will need to pay to cast Appetite of the Unnatural.