Rage Potion > Rage Elixir, since it's possible to buff Wardens with the former but not the latter.
The use of Improved Heal is odd; this isn't really a fast deck. Something that gives healing over time might be better; Sanctuary is quite nice and you don't use
in this deck. A similar argument applies for Nightmare.
Unstable Gas deals 1 damage to everything, conflicting with the use of RP to buff Wardens.
Eternity is really, really expensive. Owl's Eye can do a lot of what Eternity would in this deck and is significantly cheaper; you don't need the ability to deck out because of Shard of Patience, though if you still want that as a secondary win condition you can just make the deck bigger. Vampire Dagger could also fit as another source of healing over time. Without Eternity, Protect Artifact is unnecessary.
The deck could use Fog Shield since you note that early damage is a problem.
There isn't enough stall in the long run. Without SoPa to kill creatures this deck can only stop six-ish creatures per turn (one Antimatter, six Wardens, and one Eternity, but you only have enough quanta sources to generate about 4
per turn so you can only use four Wardens sustainably). I definitely suggest putting in another SoPa.
