I would not run less than 6 of essential cards like Nova, Photon or Immolation. The whole idea is to maximize your chance to get a good opening hand, and use it to kill your opponent quickly. Having less of these cards only reduces your chance of playing stuff on your first turn.
Well, I agree on you, but you also increase the chance that you draw quantum generation cards in your first hand, and lower your chances you'll draw a golem or other creature at the same time. Just drawing your key cards isn't enough, in my oppinion, it's drawing the right average starting hand. That's why I decreased the number of those cards.
I do not like Spark because they only last for 1 turn. This is a combo deck, you need to cast Immolation on something to get a Golem in play. Because Photons stick around, you have a better chance at using them if say you don't start with Immolation in your opening hand. Photon has the potential to do more damage than a Spark anyways. There are going to be few situations where a Spark is actually going to be more useful that Photon, and even when Spark is used for 3 damage it usually won't matter.
Spark has actually saved me a few times, which is why I like to keep them. In T50 grinds, I match up against rainbows often, and you don't tend to play more than two creatures often when you know most of them have supernovas, firestorms and otys. So you might want to immolate your photons and kick in that 9 damage when you get the chance.
I also do not like putting in cards that cost more than 2-3 of any type of quanta. In Exarp Omega's deck you would have to have played 6 cards before you can even get Dimensional Shield out. And even then, the whole point of this deck is to kill quickly... a shield or a sword that you probably won't be able to pay for and which might even get stolen and screw you is not a good addition, IMO.
What about if your rainbow opponent plays a bone wall and his sundials while spamming creatures on you? You can still grow your creatures, but you're stalled for a bit. He'll get damage through, and a shield in those situations might help, if you live long enough to play it.
Yes, your shield might get stolen, but by the time you play it, it's keeping your fingers crossed and hope it saves your life just this turn. You'd have lost if it weren't in your deck anyway, and now it might save you if you're lucky enough. In that case, you might even get to keep it the whole three turns, and win the otherwise lost match.
I have been in this situation a couple of times, so I don't see the shield as a dead card.
Graboid is actually very useful for me because I've got Earth mark, often I find I have extra Earth quanta so it is basically free to play. When it comes to buffing Golems or playing Graboid it depends on the situation and which play would net me more damage. After the 1st Lycanthrope and Forest Spirit, Graboid is the next 'swing' creature I add.
Well, I guess that's a matter of preference. I usualy tend to run out of my earth quantum fast enough, so I wouldn't add another earth based card. I'm on earth mark too, by the way.
When I'm playing PvP or T50 the 'swing cards' change a lot from the ones I posted for the AI3 deck. Deflagration is a good card for these situations.
Yes, this deck type is highly flexible, but usually when you play PvP or t50, you don't know who your next opponent will be. That's why I chose a rush deck that has something to fall back on. Sometimes it works, but I find that when it doesn't work, I'd have lost the match anyway.