Take out the Forest Spirit and add a Golden Hourglass, because you already have enough cards using
quanta and you need more card draw.
I would also take out a Rain of Fire and a Steal and add two Protect Artifacts so that anyone with Earthquake, Explosion, Steal, or cards with Destroy or Steal abilities won't completely own you. (Tip: Play one of them on your Eternity, and another on either your Pillars or an Hourglass)
If you have one, then I would add a Miracle and remove the Mind Flayer or Graboid.
You'll want to upgrade your Hourglasses and Otyughs first, so that you have more card draw and creature control.
This deck could definitely be streamlined to 45 cards or so, or even fewer -- you'll just need to experiment to find which cards aren't really necessary.
You could also take a look at Scaredgirl's almost un-upgraded Rainbow for inspiration and ideas.