A few questions.
Firstly, why the Improved Heal?
Right now it looks like your deck could take 2 different directions: Either a straight-up Destruction Cremation Rush or an EM Cremation Rush; there's really no reason to take a middle road. If you want to go the first route, then I suggest you drop that Improved Heal for a Giant Frog; the Dagger is fine because its damage/cost ratio is fantastic and possibly your best option here. If you want to go the EM route then you'll probably need at least 2 more Improved Heals; ~15% EM rate is usually obtained by any Destroyer Rush using a Vampire Dagger alone, so you'll want to aim for a number higher than 30%. Which brings me to my second point.
Do you need so many Nova/Cremation?
I've developed a Cremation Rush which used Nova as a quanta generator myself and I usually found that 4-5 Nova gave me the best results; are you sure that 6 is your best option here?
The Cremations seem like they're a bit too many. Have you tried 5 Cremations and 6 Lava Destroyers? That's the setup the current fastest Cremationbow uses and it works very well. Bottomline is that without Unupped Phoenixes I don't think 6 Cremations for 5
creatures is going to produce the best results.
If you conclude that you might need to trade out a few cards, there are a few options:
1- Chaos Power: It's a great buff and it helps keep your Destroyers/Shriekers alive past that first turn when they're most variable. The AI is much smarter now so this might be a worthy addition.
2- Minor Phoenix: The things just won't die and they're great for when you have multiple Cremations with nothing to Cremate (or maybe nothing you want to Cremate in this case).
3- A 6th Graboid: How's your
quanta? If you find you have a ridiculous amount then you may want to try another Graboid to help make that less of a problem. If not, then this probably won't help.
Anyways, if you're not interested in these suggestions then I would very much like to hear your exact reasoning for the card choices I'm worried about; this does appear to be a very good deck by the way; just in case I came across as too objective.